2093 lines
70 KiB
Python
2093 lines
70 KiB
Python
# sqlite/base.py
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# Copyright (C) 2005-2019 the SQLAlchemy authors and contributors
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# <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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r"""
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.. dialect:: sqlite
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:name: SQLite
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.. _sqlite_datetime:
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Date and Time Types
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-------------------
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SQLite does not have built-in DATE, TIME, or DATETIME types, and pysqlite does
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not provide out of the box functionality for translating values between Python
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`datetime` objects and a SQLite-supported format. SQLAlchemy's own
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:class:`~sqlalchemy.types.DateTime` and related types provide date formatting
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and parsing functionality when SQLite is used. The implementation classes are
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:class:`~.sqlite.DATETIME`, :class:`~.sqlite.DATE` and :class:`~.sqlite.TIME`.
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These types represent dates and times as ISO formatted strings, which also
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nicely support ordering. There's no reliance on typical "libc" internals for
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these functions so historical dates are fully supported.
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Ensuring Text affinity
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^^^^^^^^^^^^^^^^^^^^^^
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The DDL rendered for these types is the standard ``DATE``, ``TIME``
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and ``DATETIME`` indicators. However, custom storage formats can also be
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applied to these types. When the
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storage format is detected as containing no alpha characters, the DDL for
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these types is rendered as ``DATE_CHAR``, ``TIME_CHAR``, and ``DATETIME_CHAR``,
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so that the column continues to have textual affinity.
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.. seealso::
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`Type Affinity <http://www.sqlite.org/datatype3.html#affinity>`_ -
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in the SQLite documentation
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.. _sqlite_autoincrement:
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SQLite Auto Incrementing Behavior
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----------------------------------
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Background on SQLite's autoincrement is at: http://sqlite.org/autoinc.html
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Key concepts:
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* SQLite has an implicit "auto increment" feature that takes place for any
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non-composite primary-key column that is specifically created using
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"INTEGER PRIMARY KEY" for the type + primary key.
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* SQLite also has an explicit "AUTOINCREMENT" keyword, that is **not**
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equivalent to the implicit autoincrement feature; this keyword is not
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recommended for general use. SQLAlchemy does not render this keyword
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unless a special SQLite-specific directive is used (see below). However,
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it still requires that the column's type is named "INTEGER".
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Using the AUTOINCREMENT Keyword
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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To specifically render the AUTOINCREMENT keyword on the primary key column
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when rendering DDL, add the flag ``sqlite_autoincrement=True`` to the Table
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construct::
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Table('sometable', metadata,
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Column('id', Integer, primary_key=True),
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sqlite_autoincrement=True)
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Allowing autoincrement behavior SQLAlchemy types other than Integer/INTEGER
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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SQLite's typing model is based on naming conventions. Among other things, this
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means that any type name which contains the substring ``"INT"`` will be
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determined to be of "integer affinity". A type named ``"BIGINT"``,
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``"SPECIAL_INT"`` or even ``"XYZINTQPR"``, will be considered by SQLite to be
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of "integer" affinity. However, **the SQLite autoincrement feature, whether
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implicitly or explicitly enabled, requires that the name of the column's type
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is exactly the string "INTEGER"**. Therefore, if an application uses a type
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like :class:`.BigInteger` for a primary key, on SQLite this type will need to
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be rendered as the name ``"INTEGER"`` when emitting the initial ``CREATE
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TABLE`` statement in order for the autoincrement behavior to be available.
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One approach to achieve this is to use :class:`.Integer` on SQLite
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only using :meth:`.TypeEngine.with_variant`::
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table = Table(
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"my_table", metadata,
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Column("id", BigInteger().with_variant(Integer, "sqlite"), primary_key=True)
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)
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Another is to use a subclass of :class:`.BigInteger` that overrides its DDL
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name to be ``INTEGER`` when compiled against SQLite::
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from sqlalchemy import BigInteger
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from sqlalchemy.ext.compiler import compiles
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class SLBigInteger(BigInteger):
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pass
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@compiles(SLBigInteger, 'sqlite')
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def bi_c(element, compiler, **kw):
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return "INTEGER"
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@compiles(SLBigInteger)
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def bi_c(element, compiler, **kw):
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return compiler.visit_BIGINT(element, **kw)
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table = Table(
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"my_table", metadata,
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Column("id", SLBigInteger(), primary_key=True)
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)
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.. seealso::
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:meth:`.TypeEngine.with_variant`
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:ref:`sqlalchemy.ext.compiler_toplevel`
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`Datatypes In SQLite Version 3 <http://sqlite.org/datatype3.html>`_
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.. _sqlite_concurrency:
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Database Locking Behavior / Concurrency
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---------------------------------------
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SQLite is not designed for a high level of write concurrency. The database
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itself, being a file, is locked completely during write operations within
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transactions, meaning exactly one "connection" (in reality a file handle)
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has exclusive access to the database during this period - all other
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"connections" will be blocked during this time.
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The Python DBAPI specification also calls for a connection model that is
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always in a transaction; there is no ``connection.begin()`` method,
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only ``connection.commit()`` and ``connection.rollback()``, upon which a
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new transaction is to be begun immediately. This may seem to imply
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that the SQLite driver would in theory allow only a single filehandle on a
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particular database file at any time; however, there are several
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factors both within SQLite itself as well as within the pysqlite driver
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which loosen this restriction significantly.
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However, no matter what locking modes are used, SQLite will still always
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lock the database file once a transaction is started and DML (e.g. INSERT,
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UPDATE, DELETE) has at least been emitted, and this will block
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other transactions at least at the point that they also attempt to emit DML.
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By default, the length of time on this block is very short before it times out
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with an error.
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This behavior becomes more critical when used in conjunction with the
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SQLAlchemy ORM. SQLAlchemy's :class:`.Session` object by default runs
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within a transaction, and with its autoflush model, may emit DML preceding
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any SELECT statement. This may lead to a SQLite database that locks
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more quickly than is expected. The locking mode of SQLite and the pysqlite
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driver can be manipulated to some degree, however it should be noted that
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achieving a high degree of write-concurrency with SQLite is a losing battle.
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For more information on SQLite's lack of write concurrency by design, please
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see
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`Situations Where Another RDBMS May Work Better - High Concurrency
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<http://www.sqlite.org/whentouse.html>`_ near the bottom of the page.
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The following subsections introduce areas that are impacted by SQLite's
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file-based architecture and additionally will usually require workarounds to
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work when using the pysqlite driver.
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.. _sqlite_isolation_level:
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Transaction Isolation Level
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----------------------------
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SQLite supports "transaction isolation" in a non-standard way, along two
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axes. One is that of the
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`PRAGMA read_uncommitted <http://www.sqlite.org/pragma.html#pragma_read_uncommitted>`_
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instruction. This setting can essentially switch SQLite between its
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default mode of ``SERIALIZABLE`` isolation, and a "dirty read" isolation
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mode normally referred to as ``READ UNCOMMITTED``.
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SQLAlchemy ties into this PRAGMA statement using the
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:paramref:`.create_engine.isolation_level` parameter of :func:`.create_engine`.
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Valid values for this parameter when used with SQLite are ``"SERIALIZABLE"``
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and ``"READ UNCOMMITTED"`` corresponding to a value of 0 and 1, respectively.
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SQLite defaults to ``SERIALIZABLE``, however its behavior is impacted by
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the pysqlite driver's default behavior.
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The other axis along which SQLite's transactional locking is impacted is
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via the nature of the ``BEGIN`` statement used. The three varieties
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are "deferred", "immediate", and "exclusive", as described at
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`BEGIN TRANSACTION <http://sqlite.org/lang_transaction.html>`_. A straight
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``BEGIN`` statement uses the "deferred" mode, where the database file is
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not locked until the first read or write operation, and read access remains
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open to other transactions until the first write operation. But again,
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it is critical to note that the pysqlite driver interferes with this behavior
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by *not even emitting BEGIN* until the first write operation.
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.. warning::
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SQLite's transactional scope is impacted by unresolved
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issues in the pysqlite driver, which defers BEGIN statements to a greater
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degree than is often feasible. See the section :ref:`pysqlite_serializable`
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for techniques to work around this behavior.
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SAVEPOINT Support
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----------------------------
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SQLite supports SAVEPOINTs, which only function once a transaction is
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begun. SQLAlchemy's SAVEPOINT support is available using the
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:meth:`.Connection.begin_nested` method at the Core level, and
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:meth:`.Session.begin_nested` at the ORM level. However, SAVEPOINTs
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won't work at all with pysqlite unless workarounds are taken.
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.. warning::
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SQLite's SAVEPOINT feature is impacted by unresolved
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issues in the pysqlite driver, which defers BEGIN statements to a greater
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degree than is often feasible. See the section :ref:`pysqlite_serializable`
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for techniques to work around this behavior.
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Transactional DDL
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----------------------------
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The SQLite database supports transactional :term:`DDL` as well.
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In this case, the pysqlite driver is not only failing to start transactions,
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it also is ending any existing transaction when DDL is detected, so again,
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workarounds are required.
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.. warning::
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SQLite's transactional DDL is impacted by unresolved issues
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in the pysqlite driver, which fails to emit BEGIN and additionally
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forces a COMMIT to cancel any transaction when DDL is encountered.
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See the section :ref:`pysqlite_serializable`
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for techniques to work around this behavior.
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.. _sqlite_foreign_keys:
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Foreign Key Support
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-------------------
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SQLite supports FOREIGN KEY syntax when emitting CREATE statements for tables,
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however by default these constraints have no effect on the operation of the
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table.
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Constraint checking on SQLite has three prerequisites:
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* At least version 3.6.19 of SQLite must be in use
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* The SQLite library must be compiled *without* the SQLITE_OMIT_FOREIGN_KEY
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or SQLITE_OMIT_TRIGGER symbols enabled.
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* The ``PRAGMA foreign_keys = ON`` statement must be emitted on all
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connections before use.
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SQLAlchemy allows for the ``PRAGMA`` statement to be emitted automatically for
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new connections through the usage of events::
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from sqlalchemy.engine import Engine
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from sqlalchemy import event
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@event.listens_for(Engine, "connect")
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def set_sqlite_pragma(dbapi_connection, connection_record):
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cursor = dbapi_connection.cursor()
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cursor.execute("PRAGMA foreign_keys=ON")
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cursor.close()
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.. warning::
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When SQLite foreign keys are enabled, it is **not possible**
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to emit CREATE or DROP statements for tables that contain
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mutually-dependent foreign key constraints;
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to emit the DDL for these tables requires that ALTER TABLE be used to
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create or drop these constraints separately, for which SQLite has
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no support.
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.. seealso::
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`SQLite Foreign Key Support <http://www.sqlite.org/foreignkeys.html>`_
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- on the SQLite web site.
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:ref:`event_toplevel` - SQLAlchemy event API.
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:ref:`use_alter` - more information on SQLAlchemy's facilities for handling
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mutually-dependent foreign key constraints.
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.. _sqlite_on_conflict_ddl:
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ON CONFLICT support for constraints
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-----------------------------------
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SQLite supports a non-standard clause known as ON CONFLICT which can be applied
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to primary key, unique, check, and not null constraints. In DDL, it is
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rendered either within the "CONSTRAINT" clause or within the column definition
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itself depending on the location of the target constraint. To render this
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clause within DDL, the extension parameter ``sqlite_on_conflict`` can be
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specified with a string conflict resolution algorithm within the
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:class:`.PrimaryKeyConstraint`, :class:`.UniqueConstraint`,
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:class:`.CheckConstraint` objects. Within the :class:`.Column` object, there
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are individual parameters ``sqlite_on_conflict_not_null``,
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``sqlite_on_conflict_primary_key``, ``sqlite_on_conflict_unique`` which each
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correspond to the three types of relevant constraint types that can be
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indicated from a :class:`.Column` object.
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.. seealso::
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`ON CONFLICT <https://www.sqlite.org/lang_conflict.html>`_ - in the SQLite
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documentation
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.. versionadded:: 1.3
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The ``sqlite_on_conflict`` parameters accept a string argument which is just
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the resolution name to be chosen, which on SQLite can be one of ROLLBACK,
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ABORT, FAIL, IGNORE, and REPLACE. For example, to add a UNIQUE constraint
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that specifies the IGNORE algorithm::
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some_table = Table(
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'some_table', metadata,
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Column('id', Integer, primary_key=True),
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Column('data', Integer),
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UniqueConstraint('id', 'data', sqlite_on_conflict='IGNORE')
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)
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The above renders CREATE TABLE DDL as::
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CREATE TABLE some_table (
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id INTEGER NOT NULL,
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data INTEGER,
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PRIMARY KEY (id),
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UNIQUE (id, data) ON CONFLICT IGNORE
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)
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When using the :paramref:`.Column.unique` flag to add a UNIQUE constraint
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to a single column, the ``sqlite_on_conflict_unique`` parameter can
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be added to the :class:`.Column` as well, which will be added to the
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UNIQUE constraint in the DDL::
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some_table = Table(
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'some_table', metadata,
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Column('id', Integer, primary_key=True),
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Column('data', Integer, unique=True,
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sqlite_on_conflict_unique='IGNORE')
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)
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rendering::
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CREATE TABLE some_table (
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id INTEGER NOT NULL,
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data INTEGER,
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PRIMARY KEY (id),
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UNIQUE (data) ON CONFLICT IGNORE
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)
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To apply the FAIL algorithm for a NOT NULL constraint,
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``sqlite_on_conflict_not_null`` is used::
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some_table = Table(
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'some_table', metadata,
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Column('id', Integer, primary_key=True),
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Column('data', Integer, nullable=False,
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sqlite_on_conflict_not_null='FAIL')
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)
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this renders the column inline ON CONFLICT phrase::
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CREATE TABLE some_table (
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id INTEGER NOT NULL,
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data INTEGER NOT NULL ON CONFLICT FAIL,
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PRIMARY KEY (id)
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)
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Similarly, for an inline primary key, use ``sqlite_on_conflict_primary_key``::
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some_table = Table(
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'some_table', metadata,
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Column('id', Integer, primary_key=True,
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sqlite_on_conflict_primary_key='FAIL')
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)
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SQLAlchemy renders the PRIMARY KEY constraint separately, so the conflict
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resolution algorithm is applied to the constraint itself::
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CREATE TABLE some_table (
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id INTEGER NOT NULL,
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PRIMARY KEY (id) ON CONFLICT FAIL
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)
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.. _sqlite_type_reflection:
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Type Reflection
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---------------
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SQLite types are unlike those of most other database backends, in that
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the string name of the type usually does not correspond to a "type" in a
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one-to-one fashion. Instead, SQLite links per-column typing behavior
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to one of five so-called "type affinities" based on a string matching
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pattern for the type.
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SQLAlchemy's reflection process, when inspecting types, uses a simple
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lookup table to link the keywords returned to provided SQLAlchemy types.
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This lookup table is present within the SQLite dialect as it is for all
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other dialects. However, the SQLite dialect has a different "fallback"
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routine for when a particular type name is not located in the lookup map;
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it instead implements the SQLite "type affinity" scheme located at
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http://www.sqlite.org/datatype3.html section 2.1.
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The provided typemap will make direct associations from an exact string
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name match for the following types:
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:class:`~.types.BIGINT`, :class:`~.types.BLOB`,
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:class:`~.types.BOOLEAN`, :class:`~.types.BOOLEAN`,
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:class:`~.types.CHAR`, :class:`~.types.DATE`,
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:class:`~.types.DATETIME`, :class:`~.types.FLOAT`,
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:class:`~.types.DECIMAL`, :class:`~.types.FLOAT`,
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:class:`~.types.INTEGER`, :class:`~.types.INTEGER`,
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:class:`~.types.NUMERIC`, :class:`~.types.REAL`,
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:class:`~.types.SMALLINT`, :class:`~.types.TEXT`,
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:class:`~.types.TIME`, :class:`~.types.TIMESTAMP`,
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:class:`~.types.VARCHAR`, :class:`~.types.NVARCHAR`,
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:class:`~.types.NCHAR`
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When a type name does not match one of the above types, the "type affinity"
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lookup is used instead:
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* :class:`~.types.INTEGER` is returned if the type name includes the
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string ``INT``
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* :class:`~.types.TEXT` is returned if the type name includes the
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string ``CHAR``, ``CLOB`` or ``TEXT``
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* :class:`~.types.NullType` is returned if the type name includes the
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string ``BLOB``
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* :class:`~.types.REAL` is returned if the type name includes the string
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``REAL``, ``FLOA`` or ``DOUB``.
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* Otherwise, the :class:`~.types.NUMERIC` type is used.
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.. versionadded:: 0.9.3 Support for SQLite type affinity rules when reflecting
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columns.
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.. _sqlite_partial_index:
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Partial Indexes
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---------------
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A partial index, e.g. one which uses a WHERE clause, can be specified
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with the DDL system using the argument ``sqlite_where``::
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tbl = Table('testtbl', m, Column('data', Integer))
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idx = Index('test_idx1', tbl.c.data,
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sqlite_where=and_(tbl.c.data > 5, tbl.c.data < 10))
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The index will be rendered at create time as::
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CREATE INDEX test_idx1 ON testtbl (data)
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WHERE data > 5 AND data < 10
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.. versionadded:: 0.9.9
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.. _sqlite_dotted_column_names:
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Dotted Column Names
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-------------------
|
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Using table or column names that explicitly have periods in them is
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**not recommended**. While this is generally a bad idea for relational
|
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databases in general, as the dot is a syntactically significant character,
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the SQLite driver up until version **3.10.0** of SQLite has a bug which
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requires that SQLAlchemy filter out these dots in result sets.
|
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|
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.. versionchanged:: 1.1
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The following SQLite issue has been resolved as of version 3.10.0
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of SQLite. SQLAlchemy as of **1.1** automatically disables its internal
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workarounds based on detection of this version.
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The bug, entirely outside of SQLAlchemy, can be illustrated thusly::
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import sqlite3
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assert sqlite3.sqlite_version_info < (3, 10, 0), "bug is fixed in this version"
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conn = sqlite3.connect(":memory:")
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cursor = conn.cursor()
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cursor.execute("create table x (a integer, b integer)")
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cursor.execute("insert into x (a, b) values (1, 1)")
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cursor.execute("insert into x (a, b) values (2, 2)")
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cursor.execute("select x.a, x.b from x")
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assert [c[0] for c in cursor.description] == ['a', 'b']
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cursor.execute('''
|
|
select x.a, x.b from x where a=1
|
|
union
|
|
select x.a, x.b from x where a=2
|
|
''')
|
|
assert [c[0] for c in cursor.description] == ['a', 'b'], \
|
|
[c[0] for c in cursor.description]
|
|
|
|
The second assertion fails::
|
|
|
|
Traceback (most recent call last):
|
|
File "test.py", line 19, in <module>
|
|
[c[0] for c in cursor.description]
|
|
AssertionError: ['x.a', 'x.b']
|
|
|
|
Where above, the driver incorrectly reports the names of the columns
|
|
including the name of the table, which is entirely inconsistent vs.
|
|
when the UNION is not present.
|
|
|
|
SQLAlchemy relies upon column names being predictable in how they match
|
|
to the original statement, so the SQLAlchemy dialect has no choice but
|
|
to filter these out::
|
|
|
|
|
|
from sqlalchemy import create_engine
|
|
|
|
eng = create_engine("sqlite://")
|
|
conn = eng.connect()
|
|
|
|
conn.execute("create table x (a integer, b integer)")
|
|
conn.execute("insert into x (a, b) values (1, 1)")
|
|
conn.execute("insert into x (a, b) values (2, 2)")
|
|
|
|
result = conn.execute("select x.a, x.b from x")
|
|
assert result.keys() == ["a", "b"]
|
|
|
|
result = conn.execute('''
|
|
select x.a, x.b from x where a=1
|
|
union
|
|
select x.a, x.b from x where a=2
|
|
''')
|
|
assert result.keys() == ["a", "b"]
|
|
|
|
Note that above, even though SQLAlchemy filters out the dots, *both
|
|
names are still addressable*::
|
|
|
|
>>> row = result.first()
|
|
>>> row["a"]
|
|
1
|
|
>>> row["x.a"]
|
|
1
|
|
>>> row["b"]
|
|
1
|
|
>>> row["x.b"]
|
|
1
|
|
|
|
Therefore, the workaround applied by SQLAlchemy only impacts
|
|
:meth:`.ResultProxy.keys` and :meth:`.RowProxy.keys()` in the public API. In
|
|
the very specific case where an application is forced to use column names that
|
|
contain dots, and the functionality of :meth:`.ResultProxy.keys` and
|
|
:meth:`.RowProxy.keys()` is required to return these dotted names unmodified,
|
|
the ``sqlite_raw_colnames`` execution option may be provided, either on a
|
|
per-:class:`.Connection` basis::
|
|
|
|
result = conn.execution_options(sqlite_raw_colnames=True).execute('''
|
|
select x.a, x.b from x where a=1
|
|
union
|
|
select x.a, x.b from x where a=2
|
|
''')
|
|
assert result.keys() == ["x.a", "x.b"]
|
|
|
|
or on a per-:class:`.Engine` basis::
|
|
|
|
engine = create_engine("sqlite://", execution_options={"sqlite_raw_colnames": True})
|
|
|
|
When using the per-:class:`.Engine` execution option, note that
|
|
**Core and ORM queries that use UNION may not function properly**.
|
|
|
|
""" # noqa
|
|
|
|
import datetime
|
|
import numbers
|
|
import re
|
|
|
|
from .json import JSON
|
|
from .json import JSONIndexType
|
|
from .json import JSONPathType
|
|
from ... import exc
|
|
from ... import processors
|
|
from ... import schema as sa_schema
|
|
from ... import sql
|
|
from ... import types as sqltypes
|
|
from ... import util
|
|
from ...engine import default
|
|
from ...engine import reflection
|
|
from ...sql import ColumnElement
|
|
from ...sql import compiler
|
|
from ...types import BLOB # noqa
|
|
from ...types import BOOLEAN # noqa
|
|
from ...types import CHAR # noqa
|
|
from ...types import DECIMAL # noqa
|
|
from ...types import FLOAT # noqa
|
|
from ...types import INTEGER # noqa
|
|
from ...types import NUMERIC # noqa
|
|
from ...types import REAL # noqa
|
|
from ...types import SMALLINT # noqa
|
|
from ...types import TEXT # noqa
|
|
from ...types import TIMESTAMP # noqa
|
|
from ...types import VARCHAR # noqa
|
|
|
|
|
|
class _SQliteJson(JSON):
|
|
def result_processor(self, dialect, coltype):
|
|
default_processor = super(_SQliteJson, self).result_processor(
|
|
dialect, coltype
|
|
)
|
|
|
|
def process(value):
|
|
try:
|
|
return default_processor(value)
|
|
except TypeError:
|
|
if isinstance(value, numbers.Number):
|
|
return value
|
|
else:
|
|
raise
|
|
|
|
return process
|
|
|
|
|
|
class _DateTimeMixin(object):
|
|
_reg = None
|
|
_storage_format = None
|
|
|
|
def __init__(self, storage_format=None, regexp=None, **kw):
|
|
super(_DateTimeMixin, self).__init__(**kw)
|
|
if regexp is not None:
|
|
self._reg = re.compile(regexp)
|
|
if storage_format is not None:
|
|
self._storage_format = storage_format
|
|
|
|
@property
|
|
def format_is_text_affinity(self):
|
|
"""return True if the storage format will automatically imply
|
|
a TEXT affinity.
|
|
|
|
If the storage format contains no non-numeric characters,
|
|
it will imply a NUMERIC storage format on SQLite; in this case,
|
|
the type will generate its DDL as DATE_CHAR, DATETIME_CHAR,
|
|
TIME_CHAR.
|
|
|
|
.. versionadded:: 1.0.0
|
|
|
|
"""
|
|
spec = self._storage_format % {
|
|
"year": 0,
|
|
"month": 0,
|
|
"day": 0,
|
|
"hour": 0,
|
|
"minute": 0,
|
|
"second": 0,
|
|
"microsecond": 0,
|
|
}
|
|
return bool(re.search(r"[^0-9]", spec))
|
|
|
|
def adapt(self, cls, **kw):
|
|
if issubclass(cls, _DateTimeMixin):
|
|
if self._storage_format:
|
|
kw["storage_format"] = self._storage_format
|
|
if self._reg:
|
|
kw["regexp"] = self._reg
|
|
return super(_DateTimeMixin, self).adapt(cls, **kw)
|
|
|
|
def literal_processor(self, dialect):
|
|
bp = self.bind_processor(dialect)
|
|
|
|
def process(value):
|
|
return "'%s'" % bp(value)
|
|
|
|
return process
|
|
|
|
|
|
class DATETIME(_DateTimeMixin, sqltypes.DateTime):
|
|
r"""Represent a Python datetime object in SQLite using a string.
|
|
|
|
The default string storage format is::
|
|
|
|
"%(year)04d-%(month)02d-%(day)02d %(hour)02d:%(minute)02d:%(second)02d.%(microsecond)06d"
|
|
|
|
e.g.::
|
|
|
|
2011-03-15 12:05:57.10558
|
|
|
|
The storage format can be customized to some degree using the
|
|
``storage_format`` and ``regexp`` parameters, such as::
|
|
|
|
import re
|
|
from sqlalchemy.dialects.sqlite import DATETIME
|
|
|
|
dt = DATETIME(storage_format="%(year)04d/%(month)02d/%(day)02d "
|
|
"%(hour)02d:%(minute)02d:%(second)02d",
|
|
regexp=r"(\d+)/(\d+)/(\d+) (\d+)-(\d+)-(\d+)"
|
|
)
|
|
|
|
:param storage_format: format string which will be applied to the dict
|
|
with keys year, month, day, hour, minute, second, and microsecond.
|
|
|
|
:param regexp: regular expression which will be applied to incoming result
|
|
rows. If the regexp contains named groups, the resulting match dict is
|
|
applied to the Python datetime() constructor as keyword arguments.
|
|
Otherwise, if positional groups are used, the datetime() constructor
|
|
is called with positional arguments via
|
|
``*map(int, match_obj.groups(0))``.
|
|
|
|
""" # noqa
|
|
|
|
_storage_format = (
|
|
"%(year)04d-%(month)02d-%(day)02d "
|
|
"%(hour)02d:%(minute)02d:%(second)02d.%(microsecond)06d"
|
|
)
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
truncate_microseconds = kwargs.pop("truncate_microseconds", False)
|
|
super(DATETIME, self).__init__(*args, **kwargs)
|
|
if truncate_microseconds:
|
|
assert "storage_format" not in kwargs, (
|
|
"You can specify only "
|
|
"one of truncate_microseconds or storage_format."
|
|
)
|
|
assert "regexp" not in kwargs, (
|
|
"You can specify only one of "
|
|
"truncate_microseconds or regexp."
|
|
)
|
|
self._storage_format = (
|
|
"%(year)04d-%(month)02d-%(day)02d "
|
|
"%(hour)02d:%(minute)02d:%(second)02d"
|
|
)
|
|
|
|
def bind_processor(self, dialect):
|
|
datetime_datetime = datetime.datetime
|
|
datetime_date = datetime.date
|
|
format_ = self._storage_format
|
|
|
|
def process(value):
|
|
if value is None:
|
|
return None
|
|
elif isinstance(value, datetime_datetime):
|
|
return format_ % {
|
|
"year": value.year,
|
|
"month": value.month,
|
|
"day": value.day,
|
|
"hour": value.hour,
|
|
"minute": value.minute,
|
|
"second": value.second,
|
|
"microsecond": value.microsecond,
|
|
}
|
|
elif isinstance(value, datetime_date):
|
|
return format_ % {
|
|
"year": value.year,
|
|
"month": value.month,
|
|
"day": value.day,
|
|
"hour": 0,
|
|
"minute": 0,
|
|
"second": 0,
|
|
"microsecond": 0,
|
|
}
|
|
else:
|
|
raise TypeError(
|
|
"SQLite DateTime type only accepts Python "
|
|
"datetime and date objects as input."
|
|
)
|
|
|
|
return process
|
|
|
|
def result_processor(self, dialect, coltype):
|
|
if self._reg:
|
|
return processors.str_to_datetime_processor_factory(
|
|
self._reg, datetime.datetime
|
|
)
|
|
else:
|
|
return processors.str_to_datetime
|
|
|
|
|
|
class DATE(_DateTimeMixin, sqltypes.Date):
|
|
r"""Represent a Python date object in SQLite using a string.
|
|
|
|
The default string storage format is::
|
|
|
|
"%(year)04d-%(month)02d-%(day)02d"
|
|
|
|
e.g.::
|
|
|
|
2011-03-15
|
|
|
|
The storage format can be customized to some degree using the
|
|
``storage_format`` and ``regexp`` parameters, such as::
|
|
|
|
import re
|
|
from sqlalchemy.dialects.sqlite import DATE
|
|
|
|
d = DATE(
|
|
storage_format="%(month)02d/%(day)02d/%(year)04d",
|
|
regexp=re.compile("(?P<month>\d+)/(?P<day>\d+)/(?P<year>\d+)")
|
|
)
|
|
|
|
:param storage_format: format string which will be applied to the
|
|
dict with keys year, month, and day.
|
|
|
|
:param regexp: regular expression which will be applied to
|
|
incoming result rows. If the regexp contains named groups, the
|
|
resulting match dict is applied to the Python date() constructor
|
|
as keyword arguments. Otherwise, if positional groups are used, the
|
|
date() constructor is called with positional arguments via
|
|
``*map(int, match_obj.groups(0))``.
|
|
"""
|
|
|
|
_storage_format = "%(year)04d-%(month)02d-%(day)02d"
|
|
|
|
def bind_processor(self, dialect):
|
|
datetime_date = datetime.date
|
|
format_ = self._storage_format
|
|
|
|
def process(value):
|
|
if value is None:
|
|
return None
|
|
elif isinstance(value, datetime_date):
|
|
return format_ % {
|
|
"year": value.year,
|
|
"month": value.month,
|
|
"day": value.day,
|
|
}
|
|
else:
|
|
raise TypeError(
|
|
"SQLite Date type only accepts Python "
|
|
"date objects as input."
|
|
)
|
|
|
|
return process
|
|
|
|
def result_processor(self, dialect, coltype):
|
|
if self._reg:
|
|
return processors.str_to_datetime_processor_factory(
|
|
self._reg, datetime.date
|
|
)
|
|
else:
|
|
return processors.str_to_date
|
|
|
|
|
|
class TIME(_DateTimeMixin, sqltypes.Time):
|
|
r"""Represent a Python time object in SQLite using a string.
|
|
|
|
The default string storage format is::
|
|
|
|
"%(hour)02d:%(minute)02d:%(second)02d.%(microsecond)06d"
|
|
|
|
e.g.::
|
|
|
|
12:05:57.10558
|
|
|
|
The storage format can be customized to some degree using the
|
|
``storage_format`` and ``regexp`` parameters, such as::
|
|
|
|
import re
|
|
from sqlalchemy.dialects.sqlite import TIME
|
|
|
|
t = TIME(storage_format="%(hour)02d-%(minute)02d-"
|
|
"%(second)02d-%(microsecond)06d",
|
|
regexp=re.compile("(\d+)-(\d+)-(\d+)-(?:-(\d+))?")
|
|
)
|
|
|
|
:param storage_format: format string which will be applied to the dict
|
|
with keys hour, minute, second, and microsecond.
|
|
|
|
:param regexp: regular expression which will be applied to incoming result
|
|
rows. If the regexp contains named groups, the resulting match dict is
|
|
applied to the Python time() constructor as keyword arguments. Otherwise,
|
|
if positional groups are used, the time() constructor is called with
|
|
positional arguments via ``*map(int, match_obj.groups(0))``.
|
|
"""
|
|
|
|
_storage_format = "%(hour)02d:%(minute)02d:%(second)02d.%(microsecond)06d"
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
truncate_microseconds = kwargs.pop("truncate_microseconds", False)
|
|
super(TIME, self).__init__(*args, **kwargs)
|
|
if truncate_microseconds:
|
|
assert "storage_format" not in kwargs, (
|
|
"You can specify only "
|
|
"one of truncate_microseconds or storage_format."
|
|
)
|
|
assert "regexp" not in kwargs, (
|
|
"You can specify only one of "
|
|
"truncate_microseconds or regexp."
|
|
)
|
|
self._storage_format = "%(hour)02d:%(minute)02d:%(second)02d"
|
|
|
|
def bind_processor(self, dialect):
|
|
datetime_time = datetime.time
|
|
format_ = self._storage_format
|
|
|
|
def process(value):
|
|
if value is None:
|
|
return None
|
|
elif isinstance(value, datetime_time):
|
|
return format_ % {
|
|
"hour": value.hour,
|
|
"minute": value.minute,
|
|
"second": value.second,
|
|
"microsecond": value.microsecond,
|
|
}
|
|
else:
|
|
raise TypeError(
|
|
"SQLite Time type only accepts Python "
|
|
"time objects as input."
|
|
)
|
|
|
|
return process
|
|
|
|
def result_processor(self, dialect, coltype):
|
|
if self._reg:
|
|
return processors.str_to_datetime_processor_factory(
|
|
self._reg, datetime.time
|
|
)
|
|
else:
|
|
return processors.str_to_time
|
|
|
|
|
|
colspecs = {
|
|
sqltypes.Date: DATE,
|
|
sqltypes.DateTime: DATETIME,
|
|
sqltypes.JSON: _SQliteJson,
|
|
sqltypes.JSON.JSONIndexType: JSONIndexType,
|
|
sqltypes.JSON.JSONPathType: JSONPathType,
|
|
sqltypes.Time: TIME,
|
|
}
|
|
|
|
ischema_names = {
|
|
"BIGINT": sqltypes.BIGINT,
|
|
"BLOB": sqltypes.BLOB,
|
|
"BOOL": sqltypes.BOOLEAN,
|
|
"BOOLEAN": sqltypes.BOOLEAN,
|
|
"CHAR": sqltypes.CHAR,
|
|
"DATE": sqltypes.DATE,
|
|
"DATE_CHAR": sqltypes.DATE,
|
|
"DATETIME": sqltypes.DATETIME,
|
|
"DATETIME_CHAR": sqltypes.DATETIME,
|
|
"DOUBLE": sqltypes.FLOAT,
|
|
"DECIMAL": sqltypes.DECIMAL,
|
|
"FLOAT": sqltypes.FLOAT,
|
|
"INT": sqltypes.INTEGER,
|
|
"INTEGER": sqltypes.INTEGER,
|
|
"JSON": JSON,
|
|
"NUMERIC": sqltypes.NUMERIC,
|
|
"REAL": sqltypes.REAL,
|
|
"SMALLINT": sqltypes.SMALLINT,
|
|
"TEXT": sqltypes.TEXT,
|
|
"TIME": sqltypes.TIME,
|
|
"TIME_CHAR": sqltypes.TIME,
|
|
"TIMESTAMP": sqltypes.TIMESTAMP,
|
|
"VARCHAR": sqltypes.VARCHAR,
|
|
"NVARCHAR": sqltypes.NVARCHAR,
|
|
"NCHAR": sqltypes.NCHAR,
|
|
}
|
|
|
|
|
|
class SQLiteCompiler(compiler.SQLCompiler):
|
|
extract_map = util.update_copy(
|
|
compiler.SQLCompiler.extract_map,
|
|
{
|
|
"month": "%m",
|
|
"day": "%d",
|
|
"year": "%Y",
|
|
"second": "%S",
|
|
"hour": "%H",
|
|
"doy": "%j",
|
|
"minute": "%M",
|
|
"epoch": "%s",
|
|
"dow": "%w",
|
|
"week": "%W",
|
|
},
|
|
)
|
|
|
|
def visit_now_func(self, fn, **kw):
|
|
return "CURRENT_TIMESTAMP"
|
|
|
|
def visit_localtimestamp_func(self, func, **kw):
|
|
return 'DATETIME(CURRENT_TIMESTAMP, "localtime")'
|
|
|
|
def visit_true(self, expr, **kw):
|
|
return "1"
|
|
|
|
def visit_false(self, expr, **kw):
|
|
return "0"
|
|
|
|
def visit_char_length_func(self, fn, **kw):
|
|
return "length%s" % self.function_argspec(fn)
|
|
|
|
def visit_cast(self, cast, **kwargs):
|
|
if self.dialect.supports_cast:
|
|
return super(SQLiteCompiler, self).visit_cast(cast, **kwargs)
|
|
else:
|
|
return self.process(cast.clause, **kwargs)
|
|
|
|
def visit_extract(self, extract, **kw):
|
|
try:
|
|
return "CAST(STRFTIME('%s', %s) AS INTEGER)" % (
|
|
self.extract_map[extract.field],
|
|
self.process(extract.expr, **kw),
|
|
)
|
|
except KeyError:
|
|
raise exc.CompileError(
|
|
"%s is not a valid extract argument." % extract.field
|
|
)
|
|
|
|
def limit_clause(self, select, **kw):
|
|
text = ""
|
|
if select._limit_clause is not None:
|
|
text += "\n LIMIT " + self.process(select._limit_clause, **kw)
|
|
if select._offset_clause is not None:
|
|
if select._limit_clause is None:
|
|
text += "\n LIMIT " + self.process(sql.literal(-1))
|
|
text += " OFFSET " + self.process(select._offset_clause, **kw)
|
|
else:
|
|
text += " OFFSET " + self.process(sql.literal(0), **kw)
|
|
return text
|
|
|
|
def for_update_clause(self, select, **kw):
|
|
# sqlite has no "FOR UPDATE" AFAICT
|
|
return ""
|
|
|
|
def visit_is_distinct_from_binary(self, binary, operator, **kw):
|
|
return "%s IS NOT %s" % (
|
|
self.process(binary.left),
|
|
self.process(binary.right),
|
|
)
|
|
|
|
def visit_isnot_distinct_from_binary(self, binary, operator, **kw):
|
|
return "%s IS %s" % (
|
|
self.process(binary.left),
|
|
self.process(binary.right),
|
|
)
|
|
|
|
def visit_json_getitem_op_binary(self, binary, operator, **kw):
|
|
if binary.type._type_affinity is sqltypes.JSON:
|
|
expr = "JSON_QUOTE(JSON_EXTRACT(%s, %s))"
|
|
else:
|
|
expr = "JSON_EXTRACT(%s, %s)"
|
|
|
|
return expr % (
|
|
self.process(binary.left, **kw),
|
|
self.process(binary.right, **kw),
|
|
)
|
|
|
|
def visit_json_path_getitem_op_binary(self, binary, operator, **kw):
|
|
if binary.type._type_affinity is sqltypes.JSON:
|
|
expr = "JSON_QUOTE(JSON_EXTRACT(%s, %s))"
|
|
else:
|
|
expr = "JSON_EXTRACT(%s, %s)"
|
|
|
|
return expr % (
|
|
self.process(binary.left, **kw),
|
|
self.process(binary.right, **kw),
|
|
)
|
|
|
|
def visit_empty_set_expr(self, element_types):
|
|
return "SELECT %s FROM (SELECT %s) WHERE 1!=1" % (
|
|
", ".join("1" for type_ in element_types or [INTEGER()]),
|
|
", ".join("1" for type_ in element_types or [INTEGER()]),
|
|
)
|
|
|
|
|
|
class SQLiteDDLCompiler(compiler.DDLCompiler):
|
|
def get_column_specification(self, column, **kwargs):
|
|
if column.computed is not None:
|
|
raise exc.CompileError("SQLite does not support computed columns")
|
|
|
|
coltype = self.dialect.type_compiler.process(
|
|
column.type, type_expression=column
|
|
)
|
|
colspec = self.preparer.format_column(column) + " " + coltype
|
|
default = self.get_column_default_string(column)
|
|
if default is not None:
|
|
if isinstance(column.server_default.arg, ColumnElement):
|
|
default = "(" + default + ")"
|
|
colspec += " DEFAULT " + default
|
|
|
|
if not column.nullable:
|
|
colspec += " NOT NULL"
|
|
|
|
on_conflict_clause = column.dialect_options["sqlite"][
|
|
"on_conflict_not_null"
|
|
]
|
|
if on_conflict_clause is not None:
|
|
colspec += " ON CONFLICT " + on_conflict_clause
|
|
|
|
if column.primary_key:
|
|
if (
|
|
column.autoincrement is True
|
|
and len(column.table.primary_key.columns) != 1
|
|
):
|
|
raise exc.CompileError(
|
|
"SQLite does not support autoincrement for "
|
|
"composite primary keys"
|
|
)
|
|
|
|
if (
|
|
column.table.dialect_options["sqlite"]["autoincrement"]
|
|
and len(column.table.primary_key.columns) == 1
|
|
and issubclass(column.type._type_affinity, sqltypes.Integer)
|
|
and not column.foreign_keys
|
|
):
|
|
colspec += " PRIMARY KEY"
|
|
|
|
on_conflict_clause = column.dialect_options["sqlite"][
|
|
"on_conflict_primary_key"
|
|
]
|
|
if on_conflict_clause is not None:
|
|
colspec += " ON CONFLICT " + on_conflict_clause
|
|
|
|
colspec += " AUTOINCREMENT"
|
|
|
|
return colspec
|
|
|
|
def visit_primary_key_constraint(self, constraint):
|
|
# for columns with sqlite_autoincrement=True,
|
|
# the PRIMARY KEY constraint can only be inline
|
|
# with the column itself.
|
|
if len(constraint.columns) == 1:
|
|
c = list(constraint)[0]
|
|
if (
|
|
c.primary_key
|
|
and c.table.dialect_options["sqlite"]["autoincrement"]
|
|
and issubclass(c.type._type_affinity, sqltypes.Integer)
|
|
and not c.foreign_keys
|
|
):
|
|
return None
|
|
|
|
text = super(SQLiteDDLCompiler, self).visit_primary_key_constraint(
|
|
constraint
|
|
)
|
|
|
|
on_conflict_clause = constraint.dialect_options["sqlite"][
|
|
"on_conflict"
|
|
]
|
|
if on_conflict_clause is None and len(constraint.columns) == 1:
|
|
on_conflict_clause = list(constraint)[0].dialect_options["sqlite"][
|
|
"on_conflict_primary_key"
|
|
]
|
|
|
|
if on_conflict_clause is not None:
|
|
text += " ON CONFLICT " + on_conflict_clause
|
|
|
|
return text
|
|
|
|
def visit_unique_constraint(self, constraint):
|
|
text = super(SQLiteDDLCompiler, self).visit_unique_constraint(
|
|
constraint
|
|
)
|
|
|
|
on_conflict_clause = constraint.dialect_options["sqlite"][
|
|
"on_conflict"
|
|
]
|
|
if on_conflict_clause is None and len(constraint.columns) == 1:
|
|
on_conflict_clause = list(constraint)[0].dialect_options["sqlite"][
|
|
"on_conflict_unique"
|
|
]
|
|
|
|
if on_conflict_clause is not None:
|
|
text += " ON CONFLICT " + on_conflict_clause
|
|
|
|
return text
|
|
|
|
def visit_check_constraint(self, constraint):
|
|
text = super(SQLiteDDLCompiler, self).visit_check_constraint(
|
|
constraint
|
|
)
|
|
|
|
on_conflict_clause = constraint.dialect_options["sqlite"][
|
|
"on_conflict"
|
|
]
|
|
|
|
if on_conflict_clause is not None:
|
|
text += " ON CONFLICT " + on_conflict_clause
|
|
|
|
return text
|
|
|
|
def visit_column_check_constraint(self, constraint):
|
|
text = super(SQLiteDDLCompiler, self).visit_column_check_constraint(
|
|
constraint
|
|
)
|
|
|
|
if constraint.dialect_options["sqlite"]["on_conflict"] is not None:
|
|
raise exc.CompileError(
|
|
"SQLite does not support on conflict clause for "
|
|
"column check constraint"
|
|
)
|
|
|
|
return text
|
|
|
|
def visit_foreign_key_constraint(self, constraint):
|
|
|
|
local_table = constraint.elements[0].parent.table
|
|
remote_table = constraint.elements[0].column.table
|
|
|
|
if local_table.schema != remote_table.schema:
|
|
return None
|
|
else:
|
|
return super(SQLiteDDLCompiler, self).visit_foreign_key_constraint(
|
|
constraint
|
|
)
|
|
|
|
def define_constraint_remote_table(self, constraint, table, preparer):
|
|
"""Format the remote table clause of a CREATE CONSTRAINT clause."""
|
|
|
|
return preparer.format_table(table, use_schema=False)
|
|
|
|
def visit_create_index(
|
|
self, create, include_schema=False, include_table_schema=True
|
|
):
|
|
index = create.element
|
|
self._verify_index_table(index)
|
|
preparer = self.preparer
|
|
text = "CREATE "
|
|
if index.unique:
|
|
text += "UNIQUE "
|
|
text += "INDEX %s ON %s (%s)" % (
|
|
self._prepared_index_name(index, include_schema=True),
|
|
preparer.format_table(index.table, use_schema=False),
|
|
", ".join(
|
|
self.sql_compiler.process(
|
|
expr, include_table=False, literal_binds=True
|
|
)
|
|
for expr in index.expressions
|
|
),
|
|
)
|
|
|
|
whereclause = index.dialect_options["sqlite"]["where"]
|
|
if whereclause is not None:
|
|
where_compiled = self.sql_compiler.process(
|
|
whereclause, include_table=False, literal_binds=True
|
|
)
|
|
text += " WHERE " + where_compiled
|
|
|
|
return text
|
|
|
|
|
|
class SQLiteTypeCompiler(compiler.GenericTypeCompiler):
|
|
def visit_large_binary(self, type_, **kw):
|
|
return self.visit_BLOB(type_)
|
|
|
|
def visit_DATETIME(self, type_, **kw):
|
|
if (
|
|
not isinstance(type_, _DateTimeMixin)
|
|
or type_.format_is_text_affinity
|
|
):
|
|
return super(SQLiteTypeCompiler, self).visit_DATETIME(type_)
|
|
else:
|
|
return "DATETIME_CHAR"
|
|
|
|
def visit_DATE(self, type_, **kw):
|
|
if (
|
|
not isinstance(type_, _DateTimeMixin)
|
|
or type_.format_is_text_affinity
|
|
):
|
|
return super(SQLiteTypeCompiler, self).visit_DATE(type_)
|
|
else:
|
|
return "DATE_CHAR"
|
|
|
|
def visit_TIME(self, type_, **kw):
|
|
if (
|
|
not isinstance(type_, _DateTimeMixin)
|
|
or type_.format_is_text_affinity
|
|
):
|
|
return super(SQLiteTypeCompiler, self).visit_TIME(type_)
|
|
else:
|
|
return "TIME_CHAR"
|
|
|
|
def visit_JSON(self, type_, **kw):
|
|
# note this name provides NUMERIC affinity, not TEXT.
|
|
# should not be an issue unless the JSON value consists of a single
|
|
# numeric value. JSONTEXT can be used if this case is required.
|
|
return "JSON"
|
|
|
|
|
|
class SQLiteIdentifierPreparer(compiler.IdentifierPreparer):
|
|
reserved_words = set(
|
|
[
|
|
"add",
|
|
"after",
|
|
"all",
|
|
"alter",
|
|
"analyze",
|
|
"and",
|
|
"as",
|
|
"asc",
|
|
"attach",
|
|
"autoincrement",
|
|
"before",
|
|
"begin",
|
|
"between",
|
|
"by",
|
|
"cascade",
|
|
"case",
|
|
"cast",
|
|
"check",
|
|
"collate",
|
|
"column",
|
|
"commit",
|
|
"conflict",
|
|
"constraint",
|
|
"create",
|
|
"cross",
|
|
"current_date",
|
|
"current_time",
|
|
"current_timestamp",
|
|
"database",
|
|
"default",
|
|
"deferrable",
|
|
"deferred",
|
|
"delete",
|
|
"desc",
|
|
"detach",
|
|
"distinct",
|
|
"drop",
|
|
"each",
|
|
"else",
|
|
"end",
|
|
"escape",
|
|
"except",
|
|
"exclusive",
|
|
"explain",
|
|
"false",
|
|
"fail",
|
|
"for",
|
|
"foreign",
|
|
"from",
|
|
"full",
|
|
"glob",
|
|
"group",
|
|
"having",
|
|
"if",
|
|
"ignore",
|
|
"immediate",
|
|
"in",
|
|
"index",
|
|
"indexed",
|
|
"initially",
|
|
"inner",
|
|
"insert",
|
|
"instead",
|
|
"intersect",
|
|
"into",
|
|
"is",
|
|
"isnull",
|
|
"join",
|
|
"key",
|
|
"left",
|
|
"like",
|
|
"limit",
|
|
"match",
|
|
"natural",
|
|
"not",
|
|
"notnull",
|
|
"null",
|
|
"of",
|
|
"offset",
|
|
"on",
|
|
"or",
|
|
"order",
|
|
"outer",
|
|
"plan",
|
|
"pragma",
|
|
"primary",
|
|
"query",
|
|
"raise",
|
|
"references",
|
|
"reindex",
|
|
"rename",
|
|
"replace",
|
|
"restrict",
|
|
"right",
|
|
"rollback",
|
|
"row",
|
|
"select",
|
|
"set",
|
|
"table",
|
|
"temp",
|
|
"temporary",
|
|
"then",
|
|
"to",
|
|
"transaction",
|
|
"trigger",
|
|
"true",
|
|
"union",
|
|
"unique",
|
|
"update",
|
|
"using",
|
|
"vacuum",
|
|
"values",
|
|
"view",
|
|
"virtual",
|
|
"when",
|
|
"where",
|
|
]
|
|
)
|
|
|
|
|
|
class SQLiteExecutionContext(default.DefaultExecutionContext):
|
|
@util.memoized_property
|
|
def _preserve_raw_colnames(self):
|
|
return (
|
|
not self.dialect._broken_dotted_colnames
|
|
or self.execution_options.get("sqlite_raw_colnames", False)
|
|
)
|
|
|
|
def _translate_colname(self, colname):
|
|
# TODO: detect SQLite version 3.10.0 or greater;
|
|
# see [ticket:3633]
|
|
|
|
# adjust for dotted column names. SQLite
|
|
# in the case of UNION may store col names as
|
|
# "tablename.colname", or if using an attached database,
|
|
# "database.tablename.colname", in cursor.description
|
|
if not self._preserve_raw_colnames and "." in colname:
|
|
return colname.split(".")[-1], colname
|
|
else:
|
|
return colname, None
|
|
|
|
|
|
class SQLiteDialect(default.DefaultDialect):
|
|
name = "sqlite"
|
|
supports_alter = False
|
|
supports_unicode_statements = True
|
|
supports_unicode_binds = True
|
|
supports_default_values = True
|
|
supports_empty_insert = False
|
|
supports_cast = True
|
|
supports_multivalues_insert = True
|
|
tuple_in_values = True
|
|
|
|
default_paramstyle = "qmark"
|
|
execution_ctx_cls = SQLiteExecutionContext
|
|
statement_compiler = SQLiteCompiler
|
|
ddl_compiler = SQLiteDDLCompiler
|
|
type_compiler = SQLiteTypeCompiler
|
|
preparer = SQLiteIdentifierPreparer
|
|
ischema_names = ischema_names
|
|
colspecs = colspecs
|
|
isolation_level = None
|
|
|
|
supports_cast = True
|
|
supports_default_values = True
|
|
|
|
construct_arguments = [
|
|
(sa_schema.Table, {"autoincrement": False}),
|
|
(sa_schema.Index, {"where": None}),
|
|
(
|
|
sa_schema.Column,
|
|
{
|
|
"on_conflict_primary_key": None,
|
|
"on_conflict_not_null": None,
|
|
"on_conflict_unique": None,
|
|
},
|
|
),
|
|
(sa_schema.Constraint, {"on_conflict": None}),
|
|
]
|
|
|
|
_broken_fk_pragma_quotes = False
|
|
_broken_dotted_colnames = False
|
|
|
|
@util.deprecated_params(
|
|
_json_serializer=(
|
|
"1.3.7",
|
|
"The _json_serializer argument to the SQLite dialect has "
|
|
"been renamed to the correct name of json_serializer. The old "
|
|
"argument name will be removed in a future release.",
|
|
),
|
|
_json_deserializer=(
|
|
"1.3.7",
|
|
"The _json_deserializer argument to the SQLite dialect has "
|
|
"been renamed to the correct name of json_deserializer. The old "
|
|
"argument name will be removed in a future release.",
|
|
),
|
|
)
|
|
def __init__(
|
|
self,
|
|
isolation_level=None,
|
|
native_datetime=False,
|
|
json_serializer=None,
|
|
json_deserializer=None,
|
|
_json_serializer=None,
|
|
_json_deserializer=None,
|
|
**kwargs
|
|
):
|
|
default.DefaultDialect.__init__(self, **kwargs)
|
|
self.isolation_level = isolation_level
|
|
|
|
if _json_serializer:
|
|
json_serializer = _json_serializer
|
|
if _json_deserializer:
|
|
json_deserializer = _json_deserializer
|
|
self._json_serializer = json_serializer
|
|
self._json_deserializer = json_deserializer
|
|
|
|
# this flag used by pysqlite dialect, and perhaps others in the
|
|
# future, to indicate the driver is handling date/timestamp
|
|
# conversions (and perhaps datetime/time as well on some hypothetical
|
|
# driver ?)
|
|
self.native_datetime = native_datetime
|
|
|
|
if self.dbapi is not None:
|
|
self.supports_right_nested_joins = (
|
|
self.dbapi.sqlite_version_info >= (3, 7, 16)
|
|
)
|
|
self._broken_dotted_colnames = self.dbapi.sqlite_version_info < (
|
|
3,
|
|
10,
|
|
0,
|
|
)
|
|
self.supports_default_values = self.dbapi.sqlite_version_info >= (
|
|
3,
|
|
3,
|
|
8,
|
|
)
|
|
self.supports_cast = self.dbapi.sqlite_version_info >= (3, 2, 3)
|
|
self.supports_multivalues_insert = (
|
|
# http://www.sqlite.org/releaselog/3_7_11.html
|
|
self.dbapi.sqlite_version_info
|
|
>= (3, 7, 11)
|
|
)
|
|
# see http://www.sqlalchemy.org/trac/ticket/2568
|
|
# as well as http://www.sqlite.org/src/info/600482d161
|
|
self._broken_fk_pragma_quotes = self.dbapi.sqlite_version_info < (
|
|
3,
|
|
6,
|
|
14,
|
|
)
|
|
|
|
_isolation_lookup = {"READ UNCOMMITTED": 1, "SERIALIZABLE": 0}
|
|
|
|
def set_isolation_level(self, connection, level):
|
|
try:
|
|
isolation_level = self._isolation_lookup[level.replace("_", " ")]
|
|
except KeyError:
|
|
raise exc.ArgumentError(
|
|
"Invalid value '%s' for isolation_level. "
|
|
"Valid isolation levels for %s are %s"
|
|
% (level, self.name, ", ".join(self._isolation_lookup))
|
|
)
|
|
cursor = connection.cursor()
|
|
cursor.execute("PRAGMA read_uncommitted = %d" % isolation_level)
|
|
cursor.close()
|
|
|
|
def get_isolation_level(self, connection):
|
|
cursor = connection.cursor()
|
|
cursor.execute("PRAGMA read_uncommitted")
|
|
res = cursor.fetchone()
|
|
if res:
|
|
value = res[0]
|
|
else:
|
|
# http://www.sqlite.org/changes.html#version_3_3_3
|
|
# "Optional READ UNCOMMITTED isolation (instead of the
|
|
# default isolation level of SERIALIZABLE) and
|
|
# table level locking when database connections
|
|
# share a common cache.""
|
|
# pre-SQLite 3.3.0 default to 0
|
|
value = 0
|
|
cursor.close()
|
|
if value == 0:
|
|
return "SERIALIZABLE"
|
|
elif value == 1:
|
|
return "READ UNCOMMITTED"
|
|
else:
|
|
assert False, "Unknown isolation level %s" % value
|
|
|
|
def on_connect(self):
|
|
if self.isolation_level is not None:
|
|
|
|
def connect(conn):
|
|
self.set_isolation_level(conn, self.isolation_level)
|
|
|
|
return connect
|
|
else:
|
|
return None
|
|
|
|
@reflection.cache
|
|
def get_schema_names(self, connection, **kw):
|
|
s = "PRAGMA database_list"
|
|
dl = connection.execute(s)
|
|
|
|
return [db[1] for db in dl if db[1] != "temp"]
|
|
|
|
@reflection.cache
|
|
def get_table_names(self, connection, schema=None, **kw):
|
|
if schema is not None:
|
|
qschema = self.identifier_preparer.quote_identifier(schema)
|
|
master = "%s.sqlite_master" % qschema
|
|
else:
|
|
master = "sqlite_master"
|
|
s = ("SELECT name FROM %s " "WHERE type='table' ORDER BY name") % (
|
|
master,
|
|
)
|
|
rs = connection.execute(s)
|
|
return [row[0] for row in rs]
|
|
|
|
@reflection.cache
|
|
def get_temp_table_names(self, connection, **kw):
|
|
s = (
|
|
"SELECT name FROM sqlite_temp_master "
|
|
"WHERE type='table' ORDER BY name "
|
|
)
|
|
rs = connection.execute(s)
|
|
|
|
return [row[0] for row in rs]
|
|
|
|
@reflection.cache
|
|
def get_temp_view_names(self, connection, **kw):
|
|
s = (
|
|
"SELECT name FROM sqlite_temp_master "
|
|
"WHERE type='view' ORDER BY name "
|
|
)
|
|
rs = connection.execute(s)
|
|
|
|
return [row[0] for row in rs]
|
|
|
|
def has_table(self, connection, table_name, schema=None):
|
|
info = self._get_table_pragma(
|
|
connection, "table_info", table_name, schema=schema
|
|
)
|
|
return bool(info)
|
|
|
|
@reflection.cache
|
|
def get_view_names(self, connection, schema=None, **kw):
|
|
if schema is not None:
|
|
qschema = self.identifier_preparer.quote_identifier(schema)
|
|
master = "%s.sqlite_master" % qschema
|
|
else:
|
|
master = "sqlite_master"
|
|
s = ("SELECT name FROM %s " "WHERE type='view' ORDER BY name") % (
|
|
master,
|
|
)
|
|
rs = connection.execute(s)
|
|
|
|
return [row[0] for row in rs]
|
|
|
|
@reflection.cache
|
|
def get_view_definition(self, connection, view_name, schema=None, **kw):
|
|
if schema is not None:
|
|
qschema = self.identifier_preparer.quote_identifier(schema)
|
|
master = "%s.sqlite_master" % qschema
|
|
s = ("SELECT sql FROM %s WHERE name = '%s'" "AND type='view'") % (
|
|
master,
|
|
view_name,
|
|
)
|
|
rs = connection.execute(s)
|
|
else:
|
|
try:
|
|
s = (
|
|
"SELECT sql FROM "
|
|
" (SELECT * FROM sqlite_master UNION ALL "
|
|
" SELECT * FROM sqlite_temp_master) "
|
|
"WHERE name = '%s' "
|
|
"AND type='view'"
|
|
) % view_name
|
|
rs = connection.execute(s)
|
|
except exc.DBAPIError:
|
|
s = (
|
|
"SELECT sql FROM sqlite_master WHERE name = '%s' "
|
|
"AND type='view'"
|
|
) % view_name
|
|
rs = connection.execute(s)
|
|
|
|
result = rs.fetchall()
|
|
if result:
|
|
return result[0].sql
|
|
|
|
@reflection.cache
|
|
def get_columns(self, connection, table_name, schema=None, **kw):
|
|
info = self._get_table_pragma(
|
|
connection, "table_info", table_name, schema=schema
|
|
)
|
|
|
|
columns = []
|
|
for row in info:
|
|
(name, type_, nullable, default, primary_key) = (
|
|
row[1],
|
|
row[2].upper(),
|
|
not row[3],
|
|
row[4],
|
|
row[5],
|
|
)
|
|
|
|
columns.append(
|
|
self._get_column_info(
|
|
name, type_, nullable, default, primary_key
|
|
)
|
|
)
|
|
return columns
|
|
|
|
def _get_column_info(self, name, type_, nullable, default, primary_key):
|
|
coltype = self._resolve_type_affinity(type_)
|
|
|
|
if default is not None:
|
|
default = util.text_type(default)
|
|
|
|
return {
|
|
"name": name,
|
|
"type": coltype,
|
|
"nullable": nullable,
|
|
"default": default,
|
|
"autoincrement": "auto",
|
|
"primary_key": primary_key,
|
|
}
|
|
|
|
def _resolve_type_affinity(self, type_):
|
|
"""Return a data type from a reflected column, using affinity tules.
|
|
|
|
SQLite's goal for universal compatibility introduces some complexity
|
|
during reflection, as a column's defined type might not actually be a
|
|
type that SQLite understands - or indeed, my not be defined *at all*.
|
|
Internally, SQLite handles this with a 'data type affinity' for each
|
|
column definition, mapping to one of 'TEXT', 'NUMERIC', 'INTEGER',
|
|
'REAL', or 'NONE' (raw bits). The algorithm that determines this is
|
|
listed in http://www.sqlite.org/datatype3.html section 2.1.
|
|
|
|
This method allows SQLAlchemy to support that algorithm, while still
|
|
providing access to smarter reflection utilities by regcognizing
|
|
column definitions that SQLite only supports through affinity (like
|
|
DATE and DOUBLE).
|
|
|
|
"""
|
|
match = re.match(r"([\w ]+)(\(.*?\))?", type_)
|
|
if match:
|
|
coltype = match.group(1)
|
|
args = match.group(2)
|
|
else:
|
|
coltype = ""
|
|
args = ""
|
|
|
|
if coltype in self.ischema_names:
|
|
coltype = self.ischema_names[coltype]
|
|
elif "INT" in coltype:
|
|
coltype = sqltypes.INTEGER
|
|
elif "CHAR" in coltype or "CLOB" in coltype or "TEXT" in coltype:
|
|
coltype = sqltypes.TEXT
|
|
elif "BLOB" in coltype or not coltype:
|
|
coltype = sqltypes.NullType
|
|
elif "REAL" in coltype or "FLOA" in coltype or "DOUB" in coltype:
|
|
coltype = sqltypes.REAL
|
|
else:
|
|
coltype = sqltypes.NUMERIC
|
|
|
|
if args is not None:
|
|
args = re.findall(r"(\d+)", args)
|
|
try:
|
|
coltype = coltype(*[int(a) for a in args])
|
|
except TypeError:
|
|
util.warn(
|
|
"Could not instantiate type %s with "
|
|
"reflected arguments %s; using no arguments."
|
|
% (coltype, args)
|
|
)
|
|
coltype = coltype()
|
|
else:
|
|
coltype = coltype()
|
|
|
|
return coltype
|
|
|
|
@reflection.cache
|
|
def get_pk_constraint(self, connection, table_name, schema=None, **kw):
|
|
constraint_name = None
|
|
table_data = self._get_table_sql(connection, table_name, schema=schema)
|
|
if table_data:
|
|
PK_PATTERN = r"CONSTRAINT (\w+) PRIMARY KEY"
|
|
result = re.search(PK_PATTERN, table_data, re.I)
|
|
constraint_name = result.group(1) if result else None
|
|
|
|
cols = self.get_columns(connection, table_name, schema, **kw)
|
|
pkeys = []
|
|
for col in cols:
|
|
if col["primary_key"]:
|
|
pkeys.append(col["name"])
|
|
|
|
return {"constrained_columns": pkeys, "name": constraint_name}
|
|
|
|
@reflection.cache
|
|
def get_foreign_keys(self, connection, table_name, schema=None, **kw):
|
|
# sqlite makes this *extremely difficult*.
|
|
# First, use the pragma to get the actual FKs.
|
|
pragma_fks = self._get_table_pragma(
|
|
connection, "foreign_key_list", table_name, schema=schema
|
|
)
|
|
|
|
fks = {}
|
|
|
|
for row in pragma_fks:
|
|
(numerical_id, rtbl, lcol, rcol) = (row[0], row[2], row[3], row[4])
|
|
|
|
if not rcol:
|
|
# no referred column, which means it was not named in the
|
|
# original DDL. The referred columns of the foreign key
|
|
# constraint are therefore the primary key of the referred
|
|
# table.
|
|
referred_pk = self.get_pk_constraint(
|
|
connection, rtbl, schema=schema, **kw
|
|
)
|
|
# note that if table doesnt exist, we still get back a record,
|
|
# just it has no columns in it
|
|
referred_columns = referred_pk["constrained_columns"]
|
|
else:
|
|
# note we use this list only if this is the first column
|
|
# in the constraint. for subsequent columns we ignore the
|
|
# list and append "rcol" if present.
|
|
referred_columns = []
|
|
|
|
if self._broken_fk_pragma_quotes:
|
|
rtbl = re.sub(r"^[\"\[`\']|[\"\]`\']$", "", rtbl)
|
|
|
|
if numerical_id in fks:
|
|
fk = fks[numerical_id]
|
|
else:
|
|
fk = fks[numerical_id] = {
|
|
"name": None,
|
|
"constrained_columns": [],
|
|
"referred_schema": schema,
|
|
"referred_table": rtbl,
|
|
"referred_columns": referred_columns,
|
|
"options": {},
|
|
}
|
|
fks[numerical_id] = fk
|
|
|
|
fk["constrained_columns"].append(lcol)
|
|
|
|
if rcol:
|
|
fk["referred_columns"].append(rcol)
|
|
|
|
def fk_sig(constrained_columns, referred_table, referred_columns):
|
|
return (
|
|
tuple(constrained_columns)
|
|
+ (referred_table,)
|
|
+ tuple(referred_columns)
|
|
)
|
|
|
|
# then, parse the actual SQL and attempt to find DDL that matches
|
|
# the names as well. SQLite saves the DDL in whatever format
|
|
# it was typed in as, so need to be liberal here.
|
|
|
|
keys_by_signature = dict(
|
|
(
|
|
fk_sig(
|
|
fk["constrained_columns"],
|
|
fk["referred_table"],
|
|
fk["referred_columns"],
|
|
),
|
|
fk,
|
|
)
|
|
for fk in fks.values()
|
|
)
|
|
|
|
table_data = self._get_table_sql(connection, table_name, schema=schema)
|
|
if table_data is None:
|
|
# system tables, etc.
|
|
return []
|
|
|
|
def parse_fks():
|
|
FK_PATTERN = (
|
|
r"(?:CONSTRAINT (\w+) +)?"
|
|
r"FOREIGN KEY *\( *(.+?) *\) +"
|
|
r'REFERENCES +(?:(?:"(.+?)")|([a-z0-9_]+)) *\((.+?)\) *'
|
|
r"((?:ON (?:DELETE|UPDATE) "
|
|
r"(?:SET NULL|SET DEFAULT|CASCADE|RESTRICT|NO ACTION) *)*)"
|
|
)
|
|
for match in re.finditer(FK_PATTERN, table_data, re.I):
|
|
(
|
|
constraint_name,
|
|
constrained_columns,
|
|
referred_quoted_name,
|
|
referred_name,
|
|
referred_columns,
|
|
onupdatedelete,
|
|
) = match.group(1, 2, 3, 4, 5, 6)
|
|
constrained_columns = list(
|
|
self._find_cols_in_sig(constrained_columns)
|
|
)
|
|
if not referred_columns:
|
|
referred_columns = constrained_columns
|
|
else:
|
|
referred_columns = list(
|
|
self._find_cols_in_sig(referred_columns)
|
|
)
|
|
referred_name = referred_quoted_name or referred_name
|
|
options = {}
|
|
|
|
for token in re.split(r" *\bON\b *", onupdatedelete.upper()):
|
|
if token.startswith("DELETE"):
|
|
options["ondelete"] = token[6:].strip()
|
|
elif token.startswith("UPDATE"):
|
|
options["onupdate"] = token[6:].strip()
|
|
yield (
|
|
constraint_name,
|
|
constrained_columns,
|
|
referred_name,
|
|
referred_columns,
|
|
options,
|
|
)
|
|
|
|
fkeys = []
|
|
|
|
for (
|
|
constraint_name,
|
|
constrained_columns,
|
|
referred_name,
|
|
referred_columns,
|
|
options,
|
|
) in parse_fks():
|
|
sig = fk_sig(constrained_columns, referred_name, referred_columns)
|
|
if sig not in keys_by_signature:
|
|
util.warn(
|
|
"WARNING: SQL-parsed foreign key constraint "
|
|
"'%s' could not be located in PRAGMA "
|
|
"foreign_keys for table %s" % (sig, table_name)
|
|
)
|
|
continue
|
|
key = keys_by_signature.pop(sig)
|
|
key["name"] = constraint_name
|
|
key["options"] = options
|
|
fkeys.append(key)
|
|
# assume the remainders are the unnamed, inline constraints, just
|
|
# use them as is as it's extremely difficult to parse inline
|
|
# constraints
|
|
fkeys.extend(keys_by_signature.values())
|
|
return fkeys
|
|
|
|
def _find_cols_in_sig(self, sig):
|
|
for match in re.finditer(r'(?:"(.+?)")|([a-z0-9_]+)', sig, re.I):
|
|
yield match.group(1) or match.group(2)
|
|
|
|
@reflection.cache
|
|
def get_unique_constraints(
|
|
self, connection, table_name, schema=None, **kw
|
|
):
|
|
|
|
auto_index_by_sig = {}
|
|
for idx in self.get_indexes(
|
|
connection,
|
|
table_name,
|
|
schema=schema,
|
|
include_auto_indexes=True,
|
|
**kw
|
|
):
|
|
if not idx["name"].startswith("sqlite_autoindex"):
|
|
continue
|
|
sig = tuple(idx["column_names"])
|
|
auto_index_by_sig[sig] = idx
|
|
|
|
table_data = self._get_table_sql(
|
|
connection, table_name, schema=schema, **kw
|
|
)
|
|
if not table_data:
|
|
return []
|
|
|
|
unique_constraints = []
|
|
|
|
def parse_uqs():
|
|
UNIQUE_PATTERN = r'(?:CONSTRAINT "?(.+?)"? +)?UNIQUE *\((.+?)\)'
|
|
INLINE_UNIQUE_PATTERN = (
|
|
r'(?:(".+?")|([a-z0-9]+)) ' r"+[a-z0-9_ ]+? +UNIQUE"
|
|
)
|
|
|
|
for match in re.finditer(UNIQUE_PATTERN, table_data, re.I):
|
|
name, cols = match.group(1, 2)
|
|
yield name, list(self._find_cols_in_sig(cols))
|
|
|
|
# we need to match inlines as well, as we seek to differentiate
|
|
# a UNIQUE constraint from a UNIQUE INDEX, even though these
|
|
# are kind of the same thing :)
|
|
for match in re.finditer(INLINE_UNIQUE_PATTERN, table_data, re.I):
|
|
cols = list(
|
|
self._find_cols_in_sig(match.group(1) or match.group(2))
|
|
)
|
|
yield None, cols
|
|
|
|
for name, cols in parse_uqs():
|
|
sig = tuple(cols)
|
|
if sig in auto_index_by_sig:
|
|
auto_index_by_sig.pop(sig)
|
|
parsed_constraint = {"name": name, "column_names": cols}
|
|
unique_constraints.append(parsed_constraint)
|
|
# NOTE: auto_index_by_sig might not be empty here,
|
|
# the PRIMARY KEY may have an entry.
|
|
return unique_constraints
|
|
|
|
@reflection.cache
|
|
def get_check_constraints(self, connection, table_name, schema=None, **kw):
|
|
table_data = self._get_table_sql(
|
|
connection, table_name, schema=schema, **kw
|
|
)
|
|
if not table_data:
|
|
return []
|
|
|
|
CHECK_PATTERN = r"(?:CONSTRAINT (\w+) +)?" r"CHECK *\( *(.+) *\),? *"
|
|
check_constraints = []
|
|
# NOTE: we aren't using re.S here because we actually are
|
|
# taking advantage of each CHECK constraint being all on one
|
|
# line in the table definition in order to delineate. This
|
|
# necessarily makes assumptions as to how the CREATE TABLE
|
|
# was emitted.
|
|
for match in re.finditer(CHECK_PATTERN, table_data, re.I):
|
|
check_constraints.append(
|
|
{"sqltext": match.group(2), "name": match.group(1)}
|
|
)
|
|
|
|
return check_constraints
|
|
|
|
@reflection.cache
|
|
def get_indexes(self, connection, table_name, schema=None, **kw):
|
|
pragma_indexes = self._get_table_pragma(
|
|
connection, "index_list", table_name, schema=schema
|
|
)
|
|
indexes = []
|
|
|
|
include_auto_indexes = kw.pop("include_auto_indexes", False)
|
|
for row in pragma_indexes:
|
|
# ignore implicit primary key index.
|
|
# http://www.mail-archive.com/sqlite-users@sqlite.org/msg30517.html
|
|
if not include_auto_indexes and row[1].startswith(
|
|
"sqlite_autoindex"
|
|
):
|
|
continue
|
|
indexes.append(dict(name=row[1], column_names=[], unique=row[2]))
|
|
|
|
# loop thru unique indexes to get the column names.
|
|
for idx in list(indexes):
|
|
pragma_index = self._get_table_pragma(
|
|
connection, "index_info", idx["name"]
|
|
)
|
|
|
|
for row in pragma_index:
|
|
if row[2] is None:
|
|
util.warn(
|
|
"Skipped unsupported reflection of "
|
|
"expression-based index %s" % idx["name"]
|
|
)
|
|
indexes.remove(idx)
|
|
break
|
|
else:
|
|
idx["column_names"].append(row[2])
|
|
return indexes
|
|
|
|
@reflection.cache
|
|
def _get_table_sql(self, connection, table_name, schema=None, **kw):
|
|
if schema:
|
|
schema_expr = "%s." % (
|
|
self.identifier_preparer.quote_identifier(schema)
|
|
)
|
|
else:
|
|
schema_expr = ""
|
|
try:
|
|
s = (
|
|
"SELECT sql FROM "
|
|
" (SELECT * FROM %(schema)ssqlite_master UNION ALL "
|
|
" SELECT * FROM %(schema)ssqlite_temp_master) "
|
|
"WHERE name = '%(table)s' "
|
|
"AND type = 'table'"
|
|
% {"schema": schema_expr, "table": table_name}
|
|
)
|
|
rs = connection.execute(s)
|
|
except exc.DBAPIError:
|
|
s = (
|
|
"SELECT sql FROM %(schema)ssqlite_master "
|
|
"WHERE name = '%(table)s' "
|
|
"AND type = 'table'"
|
|
% {"schema": schema_expr, "table": table_name}
|
|
)
|
|
rs = connection.execute(s)
|
|
return rs.scalar()
|
|
|
|
def _get_table_pragma(self, connection, pragma, table_name, schema=None):
|
|
quote = self.identifier_preparer.quote_identifier
|
|
if schema is not None:
|
|
statements = ["PRAGMA %s." % quote(schema)]
|
|
else:
|
|
# because PRAGMA looks in all attached databases if no schema
|
|
# given, need to specify "main" schema, however since we want
|
|
# 'temp' tables in the same namespace as 'main', need to run
|
|
# the PRAGMA twice
|
|
statements = ["PRAGMA main.", "PRAGMA temp."]
|
|
|
|
qtable = quote(table_name)
|
|
for statement in statements:
|
|
statement = "%s%s(%s)" % (statement, pragma, qtable)
|
|
cursor = connection.execute(statement)
|
|
if not cursor._soft_closed:
|
|
# work around SQLite issue whereby cursor.description
|
|
# is blank when PRAGMA returns no rows:
|
|
# http://www.sqlite.org/cvstrac/tktview?tn=1884
|
|
result = cursor.fetchall()
|
|
else:
|
|
result = []
|
|
if result:
|
|
return result
|
|
else:
|
|
return []
|