Initial commit

venv/Lib/site-packages/sqlalchemy/dialects/sqlite/dml.py

@@ -0,0 +1,240 @@
+# dialects/sqlite/dml.py
+# Copyright (C) 2005-2024 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+from __future__ import annotations
+
+from typing import Any
+
+from .._typing import _OnConflictIndexElementsT
+from .._typing import _OnConflictIndexWhereT
+from .._typing import _OnConflictSetT
+from .._typing import _OnConflictWhereT
+from ... import util
+from ...sql import coercions
+from ...sql import roles
+from ...sql._typing import _DMLTableArgument
+from ...sql.base import _exclusive_against
+from ...sql.base import _generative
+from ...sql.base import ColumnCollection
+from ...sql.base import ReadOnlyColumnCollection
+from ...sql.dml import Insert as StandardInsert
+from ...sql.elements import ClauseElement
+from ...sql.elements import KeyedColumnElement
+from ...sql.expression import alias
+from ...util.typing import Self
+
+__all__ = ("Insert", "insert")
+
+
+def insert(table: _DMLTableArgument) -> Insert:
+    """Construct a sqlite-specific variant :class:`_sqlite.Insert`
+    construct.
+
+    .. container:: inherited_member
+
+        The :func:`sqlalchemy.dialects.sqlite.insert` function creates
+        a :class:`sqlalchemy.dialects.sqlite.Insert`.  This class is based
+        on the dialect-agnostic :class:`_sql.Insert` construct which may
+        be constructed using the :func:`_sql.insert` function in
+        SQLAlchemy Core.
+
+    The :class:`_sqlite.Insert` construct includes additional methods
+    :meth:`_sqlite.Insert.on_conflict_do_update`,
+    :meth:`_sqlite.Insert.on_conflict_do_nothing`.
+
+    """
+    return Insert(table)
+
+
+class Insert(StandardInsert):
+    """SQLite-specific implementation of INSERT.
+
+    Adds methods for SQLite-specific syntaxes such as ON CONFLICT.
+
+    The :class:`_sqlite.Insert` object is created using the
+    :func:`sqlalchemy.dialects.sqlite.insert` function.
+
+    .. versionadded:: 1.4
+
+    .. seealso::
+
+        :ref:`sqlite_on_conflict_insert`
+
+    """
+
+    stringify_dialect = "sqlite"
+    inherit_cache = False
+
+    @util.memoized_property
+    def excluded(
+        self,
+    ) -> ReadOnlyColumnCollection[str, KeyedColumnElement[Any]]:
+        """Provide the ``excluded`` namespace for an ON CONFLICT statement
+
+        SQLite's ON CONFLICT clause allows reference to the row that would
+        be inserted, known as ``excluded``.  This attribute provides
+        all columns in this row to be referenceable.
+
+        .. tip::  The :attr:`_sqlite.Insert.excluded` attribute is an instance
+            of :class:`_expression.ColumnCollection`, which provides an
+            interface the same as that of the :attr:`_schema.Table.c`
+            collection described at :ref:`metadata_tables_and_columns`.
+            With this collection, ordinary names are accessible like attributes
+            (e.g. ``stmt.excluded.some_column``), but special names and
+            dictionary method names should be accessed using indexed access,
+            such as ``stmt.excluded["column name"]`` or
+            ``stmt.excluded["values"]``.  See the docstring for
+            :class:`_expression.ColumnCollection` for further examples.
+
+        """
+        return alias(self.table, name="excluded").columns
+
+    _on_conflict_exclusive = _exclusive_against(
+        "_post_values_clause",
+        msgs={
+            "_post_values_clause": "This Insert construct already has "
+            "an ON CONFLICT clause established"
+        },
+    )
+
+    @_generative
+    @_on_conflict_exclusive
+    def on_conflict_do_update(
+        self,
+        index_elements: _OnConflictIndexElementsT = None,
+        index_where: _OnConflictIndexWhereT = None,
+        set_: _OnConflictSetT = None,
+        where: _OnConflictWhereT = None,
+    ) -> Self:
+        r"""
+        Specifies a DO UPDATE SET action for ON CONFLICT clause.
+
+        :param index_elements:
+         A sequence consisting of string column names, :class:`_schema.Column`
+         objects, or other column expression objects that will be used
+         to infer a target index or unique constraint.
+
+        :param index_where:
+         Additional WHERE criterion that can be used to infer a
+         conditional target index.
+
+        :param set\_:
+         A dictionary or other mapping object
+         where the keys are either names of columns in the target table,
+         or :class:`_schema.Column` objects or other ORM-mapped columns
+         matching that of the target table, and expressions or literals
+         as values, specifying the ``SET`` actions to take.
+
+         .. versionadded:: 1.4 The
+            :paramref:`_sqlite.Insert.on_conflict_do_update.set_`
+            parameter supports :class:`_schema.Column` objects from the target
+            :class:`_schema.Table` as keys.
+
+         .. warning:: This dictionary does **not** take into account
+            Python-specified default UPDATE values or generation functions,
+            e.g. those specified using :paramref:`_schema.Column.onupdate`.
+            These values will not be exercised for an ON CONFLICT style of
+            UPDATE, unless they are manually specified in the
+            :paramref:`.Insert.on_conflict_do_update.set_` dictionary.
+
+        :param where:
+         Optional argument. If present, can be a literal SQL
+         string or an acceptable expression for a ``WHERE`` clause
+         that restricts the rows affected by ``DO UPDATE SET``. Rows
+         not meeting the ``WHERE`` condition will not be updated
+         (effectively a ``DO NOTHING`` for those rows).
+
+        """
+
+        self._post_values_clause = OnConflictDoUpdate(
+            index_elements, index_where, set_, where
+        )
+        return self
+
+    @_generative
+    @_on_conflict_exclusive
+    def on_conflict_do_nothing(
+        self,
+        index_elements: _OnConflictIndexElementsT = None,
+        index_where: _OnConflictIndexWhereT = None,
+    ) -> Self:
+        """
+        Specifies a DO NOTHING action for ON CONFLICT clause.
+
+        :param index_elements:
+         A sequence consisting of string column names, :class:`_schema.Column`
+         objects, or other column expression objects that will be used
+         to infer a target index or unique constraint.
+
+        :param index_where:
+         Additional WHERE criterion that can be used to infer a
+         conditional target index.
+
+        """
+
+        self._post_values_clause = OnConflictDoNothing(
+            index_elements, index_where
+        )
+        return self
+
+
+class OnConflictClause(ClauseElement):
+    stringify_dialect = "sqlite"
+
+    constraint_target: None
+    inferred_target_elements: _OnConflictIndexElementsT
+    inferred_target_whereclause: _OnConflictIndexWhereT
+
+    def __init__(
+        self,
+        index_elements: _OnConflictIndexElementsT = None,
+        index_where: _OnConflictIndexWhereT = None,
+    ):
+        if index_elements is not None:
+            self.constraint_target = None
+            self.inferred_target_elements = index_elements
+            self.inferred_target_whereclause = index_where
+        else:
+            self.constraint_target = self.inferred_target_elements = (
+                self.inferred_target_whereclause
+            ) = None
+
+
+class OnConflictDoNothing(OnConflictClause):
+    __visit_name__ = "on_conflict_do_nothing"
+
+
+class OnConflictDoUpdate(OnConflictClause):
+    __visit_name__ = "on_conflict_do_update"
+
+    def __init__(
+        self,
+        index_elements: _OnConflictIndexElementsT = None,
+        index_where: _OnConflictIndexWhereT = None,
+        set_: _OnConflictSetT = None,
+        where: _OnConflictWhereT = None,
+    ):
+        super().__init__(
+            index_elements=index_elements,
+            index_where=index_where,
+        )
+
+        if isinstance(set_, dict):
+            if not set_:
+                raise ValueError("set parameter dictionary must not be empty")
+        elif isinstance(set_, ColumnCollection):
+            set_ = dict(set_)
+        else:
+            raise ValueError(
+                "set parameter must be a non-empty dictionary "
+                "or a ColumnCollection such as the `.c.` collection "
+                "of a Table object"
+            )
+        self.update_values_to_set = [
+            (coercions.expect(roles.DMLColumnRole, key), value)
+            for key, value in set_.items()
+        ]
+        self.update_whereclause = where