JezK
Edit File: dml.py
# sql/dml.py # Copyright (C) 2009-2024 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 """ Provide :class:`_expression.Insert`, :class:`_expression.Update` and :class:`_expression.Delete`. """ from sqlalchemy.types import NullType from . import coercions from . import roles from . import util as sql_util from .base import _entity_namespace_key from .base import _exclusive_against from .base import _from_objects from .base import _generative from .base import ColumnCollection from .base import CompileState from .base import DialectKWArgs from .base import Executable from .base import HasCompileState from .elements import BooleanClauseList from .elements import ClauseElement from .elements import Null from .selectable import HasCTE from .selectable import HasPrefixes from .selectable import ReturnsRows from .visitors import InternalTraversal from .. import exc from .. import util from ..util import collections_abc class DMLState(CompileState): _no_parameters = True _dict_parameters = None _multi_parameters = None _ordered_values = None _parameter_ordering = None _has_multi_parameters = False isupdate = False isdelete = False isinsert = False def __init__(self, statement, compiler, **kw): raise NotImplementedError() @classmethod def get_entity_description(cls, statement): return {"name": statement.table.name, "table": statement.table} @classmethod def get_returning_column_descriptions(cls, statement): return [ { "name": c.key, "type": c.type, "expr": c, } for c in statement._all_selected_columns ] @property def dml_table(self): return self.statement.table @classmethod def _get_crud_kv_pairs(cls, statement, kv_iterator): return [ ( coercions.expect(roles.DMLColumnRole, k), coercions.expect( roles.ExpressionElementRole, v, type_=NullType(), is_crud=True, ), ) for k, v in kv_iterator ] def _make_extra_froms(self, statement): froms = [] all_tables = list(sql_util.tables_from_leftmost(statement.table)) seen = {all_tables[0]} for crit in statement._where_criteria: for item in _from_objects(crit): if not seen.intersection(item._cloned_set): froms.append(item) seen.update(item._cloned_set) froms.extend(all_tables[1:]) return froms def _process_multi_values(self, statement): if not statement._supports_multi_parameters: raise exc.InvalidRequestError( "%s construct does not support " "multiple parameter sets." % statement.__visit_name__.upper() ) for parameters in statement._multi_values: multi_parameters = [ { c.key: value for c, value in zip(statement.table.c, parameter_set) } if isinstance(parameter_set, collections_abc.Sequence) else parameter_set for parameter_set in parameters ] if self._no_parameters: self._no_parameters = False self._has_multi_parameters = True self._multi_parameters = multi_parameters self._dict_parameters = self._multi_parameters[0] elif not self._has_multi_parameters: self._cant_mix_formats_error() else: self._multi_parameters.extend(multi_parameters) def _process_values(self, statement): if self._no_parameters: self._has_multi_parameters = False self._dict_parameters = statement._values self._no_parameters = False elif self._has_multi_parameters: self._cant_mix_formats_error() def _process_ordered_values(self, statement): parameters = statement._ordered_values if self._no_parameters: self._no_parameters = False self._dict_parameters = dict(parameters) self._ordered_values = parameters self._parameter_ordering = [key for key, value in parameters] elif self._has_multi_parameters: self._cant_mix_formats_error() else: raise exc.InvalidRequestError( "Can only invoke ordered_values() once, and not mixed " "with any other values() call" ) def _process_select_values(self, statement): parameters = { coercions.expect(roles.DMLColumnRole, name, as_key=True): Null() for name in statement._select_names } if self._no_parameters: self._no_parameters = False self._dict_parameters = parameters else: # this condition normally not reachable as the Insert # does not allow this construction to occur assert False, "This statement already has parameters" def _cant_mix_formats_error(self): raise exc.InvalidRequestError( "Can't mix single and multiple VALUES " "formats in one INSERT statement; one style appends to a " "list while the other replaces values, so the intent is " "ambiguous." ) @CompileState.plugin_for("default", "insert") class InsertDMLState(DMLState): isinsert = True include_table_with_column_exprs = False def __init__(self, statement, compiler, **kw): self.statement = statement self.isinsert = True if statement._select_names: self._process_select_values(statement) if statement._values is not None: self._process_values(statement) if statement._multi_values: self._process_multi_values(statement) @util.memoized_property def _insert_col_keys(self): # this is also done in crud.py -> _key_getters_for_crud_column return [ coercions.expect_as_key(roles.DMLColumnRole, col) for col in self._dict_parameters ] @CompileState.plugin_for("default", "update") class UpdateDMLState(DMLState): isupdate = True include_table_with_column_exprs = False def __init__(self, statement, compiler, **kw): self.statement = statement self.isupdate = True self._preserve_parameter_order = statement._preserve_parameter_order if statement._ordered_values is not None: self._process_ordered_values(statement) elif statement._values is not None: self._process_values(statement) elif statement._multi_values: self._process_multi_values(statement) self._extra_froms = ef = self._make_extra_froms(statement) self.is_multitable = mt = ef and self._dict_parameters self.include_table_with_column_exprs = ( mt and compiler.render_table_with_column_in_update_from ) @CompileState.plugin_for("default", "delete") class DeleteDMLState(DMLState): isdelete = True def __init__(self, statement, compiler, **kw): self.statement = statement self.isdelete = True self._extra_froms = self._make_extra_froms(statement) class UpdateBase( roles.DMLRole, HasCTE, HasCompileState, DialectKWArgs, HasPrefixes, ReturnsRows, Executable, ClauseElement, ): """Form the base for ``INSERT``, ``UPDATE``, and ``DELETE`` statements.""" __visit_name__ = "update_base" _execution_options = Executable._execution_options.union( {"autocommit": True} ) _hints = util.immutabledict() named_with_column = False _return_defaults = False _return_defaults_columns = None _returning = () is_dml = True @classmethod def _constructor_20_deprecations(cls, fn_name, clsname, names): param_to_method_lookup = dict( whereclause=( "The :paramref:`%(func)s.whereclause` parameter " "will be removed " "in SQLAlchemy 2.0. Please refer to the " ":meth:`%(classname)s.where` method." ), values=( "The :paramref:`%(func)s.values` parameter will be removed " "in SQLAlchemy 2.0. Please refer to the " ":meth:`%(classname)s.values` method." ), bind=( "The :paramref:`%(func)s.bind` parameter will be removed in " "SQLAlchemy 2.0. Please use explicit connection execution." ), inline=( "The :paramref:`%(func)s.inline` parameter will be " "removed in " "SQLAlchemy 2.0. Please use the " ":meth:`%(classname)s.inline` method." ), prefixes=( "The :paramref:`%(func)s.prefixes parameter will be " "removed in " "SQLAlchemy 2.0. Please use the " ":meth:`%(classname)s.prefix_with` " "method." ), return_defaults=( "The :paramref:`%(func)s.return_defaults` parameter will be " "removed in SQLAlchemy 2.0. Please use the " ":meth:`%(classname)s.return_defaults` method." ), returning=( "The :paramref:`%(func)s.returning` parameter will be " "removed in SQLAlchemy 2.0. Please use the " ":meth:`%(classname)s.returning`` method." ), preserve_parameter_order=( "The :paramref:`%(func)s.preserve_parameter_order` parameter " "will be removed in SQLAlchemy 2.0. Use the " ":meth:`%(classname)s.ordered_values` method with a list " "of tuples. " ), ) return util.deprecated_params( **{ name: ( "2.0", param_to_method_lookup[name] % { "func": "_expression.%s" % fn_name, "classname": "_expression.%s" % clsname, }, ) for name in names } ) def _generate_fromclause_column_proxies(self, fromclause): fromclause._columns._populate_separate_keys( col._make_proxy(fromclause) for col in self._returning ) def params(self, *arg, **kw): """Set the parameters for the statement. This method raises ``NotImplementedError`` on the base class, and is overridden by :class:`.ValuesBase` to provide the SET/VALUES clause of UPDATE and INSERT. """ raise NotImplementedError( "params() is not supported for INSERT/UPDATE/DELETE statements." " To set the values for an INSERT or UPDATE statement, use" " stmt.values(**parameters)." ) @_generative def with_dialect_options(self, **opt): """Add dialect options to this INSERT/UPDATE/DELETE object. e.g.:: upd = table.update().dialect_options(mysql_limit=10) .. versionadded: 1.4 - this method supersedes the dialect options associated with the constructor. """ self._validate_dialect_kwargs(opt) def _validate_dialect_kwargs_deprecated(self, dialect_kw): util.warn_deprecated_20( "Passing dialect keyword arguments directly to the " "%s constructor is deprecated and will be removed in SQLAlchemy " "2.0. Please use the ``with_dialect_options()`` method." % (self.__class__.__name__) ) self._validate_dialect_kwargs(dialect_kw) def bind(self): """Return a 'bind' linked to this :class:`.UpdateBase` or a :class:`_schema.Table` associated with it. """ return self._bind or self.table.bind def _set_bind(self, bind): self._bind = bind bind = property(bind, _set_bind) @_generative def returning(self, *cols): r"""Add a :term:`RETURNING` or equivalent clause to this statement. e.g.: .. sourcecode:: pycon+sql >>> stmt = ( ... table.update() ... .where(table.c.data == "value") ... .values(status="X") ... .returning(table.c.server_flag, table.c.updated_timestamp) ... ) >>> print(stmt) UPDATE some_table SET status=:status WHERE some_table.data = :data_1 RETURNING some_table.server_flag, some_table.updated_timestamp The method may be invoked multiple times to add new entries to the list of expressions to be returned. .. versionadded:: 1.4.0b2 The method may be invoked multiple times to add new entries to the list of expressions to be returned. The given collection of column expressions should be derived from the table that is the target of the INSERT, UPDATE, or DELETE. While :class:`_schema.Column` objects are typical, the elements can also be expressions: .. sourcecode:: pycon+sql >>> stmt = table.insert().returning( ... (table.c.first_name + " " + table.c.last_name).label("fullname") ... ) >>> print(stmt) INSERT INTO some_table (first_name, last_name) VALUES (:first_name, :last_name) RETURNING some_table.first_name || :first_name_1 || some_table.last_name AS fullname Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted. Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using :meth:`_engine.CursorResult.fetchone` and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided. Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING. .. seealso:: :meth:`.ValuesBase.return_defaults` - an alternative method tailored towards efficient fetching of server-side defaults and triggers for single-row INSERTs or UPDATEs. :ref:`tutorial_insert_returning` - in the :ref:`unified_tutorial` """ # noqa: E501 if self._return_defaults: raise exc.InvalidRequestError( "return_defaults() is already configured on this statement" ) self._returning += tuple( coercions.expect(roles.ColumnsClauseRole, c) for c in cols ) @property def _all_selected_columns(self): return self._returning @property def exported_columns(self): """Return the RETURNING columns as a column collection for this statement. .. versionadded:: 1.4 """ # TODO: no coverage here return ColumnCollection( (c.key, c) for c in self._all_selected_columns ).as_immutable() @_generative def with_hint(self, text, selectable=None, dialect_name="*"): """Add a table hint for a single table to this INSERT/UPDATE/DELETE statement. .. note:: :meth:`.UpdateBase.with_hint` currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use :meth:`.UpdateBase.prefix_with`. The text of the hint is rendered in the appropriate location for the database backend in use, relative to the :class:`_schema.Table` that is the subject of this statement, or optionally to that of the given :class:`_schema.Table` passed as the ``selectable`` argument. The ``dialect_name`` option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:: mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql") :param text: Text of the hint. :param selectable: optional :class:`_schema.Table` that specifies an element of the FROM clause within an UPDATE or DELETE to be the subject of the hint - applies only to certain backends. :param dialect_name: defaults to ``*``, if specified as the name of a particular dialect, will apply these hints only when that dialect is in use. """ if selectable is None: selectable = self.table self._hints = self._hints.union({(selectable, dialect_name): text}) @property def entity_description(self): """Return a :term:`plugin-enabled` description of the table and/or entity which this DML construct is operating against. This attribute is generally useful when using the ORM, as an extended structure which includes information about mapped entities is returned. The section :ref:`queryguide_inspection` contains more background. For a Core statement, the structure returned by this accessor is derived from the :attr:`.UpdateBase.table` attribute, and refers to the :class:`.Table` being inserted, updated, or deleted:: >>> stmt = insert(user_table) >>> stmt.entity_description { "name": "user_table", "table": Table("user_table", ...) } .. versionadded:: 1.4.33 .. seealso:: :attr:`.UpdateBase.returning_column_descriptions` :attr:`.Select.column_descriptions` - entity information for a :func:`.select` construct :ref:`queryguide_inspection` - ORM background """ meth = DMLState.get_plugin_class(self).get_entity_description return meth(self) @property def returning_column_descriptions(self): """Return a :term:`plugin-enabled` description of the columns which this DML construct is RETURNING against, in other words the expressions established as part of :meth:`.UpdateBase.returning`. This attribute is generally useful when using the ORM, as an extended structure which includes information about mapped entities is returned. The section :ref:`queryguide_inspection` contains more background. For a Core statement, the structure returned by this accessor is derived from the same objects that are returned by the :attr:`.UpdateBase.exported_columns` accessor:: >>> stmt = insert(user_table).returning(user_table.c.id, user_table.c.name) >>> stmt.entity_description [ { "name": "id", "type": Integer, "expr": Column("id", Integer(), table=<user>, ...) }, { "name": "name", "type": String(), "expr": Column("name", String(), table=<user>, ...) }, ] .. versionadded:: 1.4.33 .. seealso:: :attr:`.UpdateBase.entity_description` :attr:`.Select.column_descriptions` - entity information for a :func:`.select` construct :ref:`queryguide_inspection` - ORM background """ # noqa: E501 meth = DMLState.get_plugin_class( self ).get_returning_column_descriptions return meth(self) class ValuesBase(UpdateBase): """Supplies support for :meth:`.ValuesBase.values` to INSERT and UPDATE constructs.""" __visit_name__ = "values_base" _supports_multi_parameters = False _preserve_parameter_order = False select = None _post_values_clause = None _values = None _multi_values = () _ordered_values = None _select_names = None _returning = () def __init__(self, table, values, prefixes): self.table = coercions.expect( roles.DMLTableRole, table, apply_propagate_attrs=self ) if values is not None: self.values.non_generative(self, values) if prefixes: self._setup_prefixes(prefixes) @_generative @_exclusive_against( "_select_names", "_ordered_values", msgs={ "_select_names": "This construct already inserts from a SELECT", "_ordered_values": "This statement already has ordered " "values present", }, ) def values(self, *args, **kwargs): r"""Specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE. Note that the :class:`_expression.Insert` and :class:`_expression.Update` constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed to :meth:`_engine.Connection.execute`. However, the :meth:`.ValuesBase.values` method can be used to "fix" a particular set of parameters into the statement. Multiple calls to :meth:`.ValuesBase.values` will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based "multiple values" construct, each new list of values is extended onto the existing list of values. :param \**kwargs: key value pairs representing the string key of a :class:`_schema.Column` mapped to the value to be rendered into the VALUES or SET clause:: users.insert().values(name="some name") users.update().where(users.c.id==5).values(name="some name") :param \*args: As an alternative to passing key/value parameters, a dictionary, tuple, or list of dictionaries or tuples can be passed as a single positional argument in order to form the VALUES or SET clause of the statement. The forms that are accepted vary based on whether this is an :class:`_expression.Insert` or an :class:`_expression.Update` construct. For either an :class:`_expression.Insert` or :class:`_expression.Update` construct, a single dictionary can be passed, which works the same as that of the kwargs form:: users.insert().values({"name": "some name"}) users.update().values({"name": "some new name"}) Also for either form but more typically for the :class:`_expression.Insert` construct, a tuple that contains an entry for every column in the table is also accepted:: users.insert().values((5, "some name")) The :class:`_expression.Insert` construct also supports being passed a list of dictionaries or full-table-tuples, which on the server will render the less common SQL syntax of "multiple values" - this syntax is supported on backends such as SQLite, PostgreSQL, MySQL, but not necessarily others:: users.insert().values([ {"name": "some name"}, {"name": "some other name"}, {"name": "yet another name"}, ]) The above form would render a multiple VALUES statement similar to:: INSERT INTO users (name) VALUES (:name_1), (:name_2), (:name_3) It is essential to note that **passing multiple values is NOT the same as using traditional executemany() form**. The above syntax is a **special** syntax not typically used. To emit an INSERT statement against multiple rows, the normal method is to pass a multiple values list to the :meth:`_engine.Connection.execute` method, which is supported by all database backends and is generally more efficient for a very large number of parameters. .. seealso:: :ref:`tutorial_multiple_parameters` - an introduction to the traditional Core method of multiple parameter set invocation for INSERTs and other statements. .. versionchanged:: 1.0.0 an INSERT that uses a multiple-VALUES clause, even a list of length one, implies that the :paramref:`_expression.Insert.inline` flag is set to True, indicating that the statement will not attempt to fetch the "last inserted primary key" or other defaults. The statement deals with an arbitrary number of rows, so the :attr:`_engine.CursorResult.inserted_primary_key` accessor does not apply. .. versionchanged:: 1.0.0 A multiple-VALUES INSERT now supports columns with Python side default values and callables in the same way as that of an "executemany" style of invocation; the callable is invoked for each row. See :ref:`bug_3288` for other details. The UPDATE construct also supports rendering the SET parameters in a specific order. For this feature refer to the :meth:`_expression.Update.ordered_values` method. .. seealso:: :meth:`_expression.Update.ordered_values` """ if args: # positional case. this is currently expensive. we don't # yet have positional-only args so we have to check the length. # then we need to check multiparams vs. single dictionary. # since the parameter format is needed in order to determine # a cache key, we need to determine this up front. arg = args[0] if kwargs: raise exc.ArgumentError( "Can't pass positional and kwargs to values() " "simultaneously" ) elif len(args) > 1: raise exc.ArgumentError( "Only a single dictionary/tuple or list of " "dictionaries/tuples is accepted positionally." ) elif not self._preserve_parameter_order and isinstance( arg, collections_abc.Sequence ): if arg and isinstance(arg[0], (list, dict, tuple)): self._multi_values += (arg,) return # tuple values arg = {c.key: value for c, value in zip(self.table.c, arg)} elif self._preserve_parameter_order and not isinstance( arg, collections_abc.Sequence ): raise ValueError( "When preserve_parameter_order is True, " "values() only accepts a list of 2-tuples" ) else: # kwarg path. this is the most common path for non-multi-params # so this is fairly quick. arg = kwargs if args: raise exc.ArgumentError( "Only a single dictionary/tuple or list of " "dictionaries/tuples is accepted positionally." ) # for top level values(), convert literals to anonymous bound # parameters at statement construction time, so that these values can # participate in the cache key process like any other ClauseElement. # crud.py now intercepts bound parameters with unique=True from here # and ensures they get the "crud"-style name when rendered. kv_generator = DMLState.get_plugin_class(self)._get_crud_kv_pairs if self._preserve_parameter_order: self._ordered_values = kv_generator(self, arg) else: arg = {k: v for k, v in kv_generator(self, arg.items())} if self._values: self._values = self._values.union(arg) else: self._values = util.immutabledict(arg) @_generative @_exclusive_against( "_returning", msgs={ "_returning": "RETURNING is already configured on this statement" }, defaults={"_returning": _returning}, ) def return_defaults(self, *cols): """Make use of a :term:`RETURNING` clause for the purpose of fetching server-side expressions and defaults. E.g.:: stmt = table.insert().values(data='newdata').return_defaults() result = connection.execute(stmt) server_created_at = result.returned_defaults['created_at'] When used against a backend that supports RETURNING, all column values generated by SQL expression or server-side-default will be added to any existing RETURNING clause, provided that :meth:`.UpdateBase.returning` is not used simultaneously. The column values will then be available on the result using the :attr:`_engine.CursorResult.returned_defaults` accessor as a dictionary, referring to values keyed to the :class:`_schema.Column` object as well as its ``.key``. This method differs from :meth:`.UpdateBase.returning` in these ways: 1. :meth:`.ValuesBase.return_defaults` is only intended for use with an INSERT or an UPDATE statement that matches exactly one row per parameter set. While the RETURNING construct in the general sense supports multiple rows for a multi-row UPDATE or DELETE statement, or for special cases of INSERT that return multiple rows (e.g. INSERT from SELECT, multi-valued VALUES clause), :meth:`.ValuesBase.return_defaults` is intended only for an "ORM-style" single-row INSERT/UPDATE statement. The row returned by the statement is also consumed implicitly when :meth:`.ValuesBase.return_defaults` is used. By contrast, :meth:`.UpdateBase.returning` leaves the RETURNING result-set intact with a collection of any number of rows. 2. It is compatible with the existing logic to fetch auto-generated primary key values, also known as "implicit returning". Backends that support RETURNING will automatically make use of RETURNING in order to fetch the value of newly generated primary keys; while the :meth:`.UpdateBase.returning` method circumvents this behavior, :meth:`.ValuesBase.return_defaults` leaves it intact. 3. It can be called against any backend. Backends that don't support RETURNING will skip the usage of the feature, rather than raising an exception. The return value of :attr:`_engine.CursorResult.returned_defaults` will be ``None`` 4. An INSERT statement invoked with executemany() is supported if the backend database driver supports the ``insert_executemany_returning`` feature, currently this includes PostgreSQL with psycopg2. When executemany is used, the :attr:`_engine.CursorResult.returned_defaults_rows` and :attr:`_engine.CursorResult.inserted_primary_key_rows` accessors will return the inserted defaults and primary keys. .. versionadded:: 1.4 :meth:`.ValuesBase.return_defaults` is used by the ORM to provide an efficient implementation for the ``eager_defaults`` feature of :func:`.mapper`. :param cols: optional list of column key names or :class:`_schema.Column` objects. If omitted, all column expressions evaluated on the server are added to the returning list. .. versionadded:: 0.9.0 .. seealso:: :meth:`.UpdateBase.returning` :attr:`_engine.CursorResult.returned_defaults` :attr:`_engine.CursorResult.returned_defaults_rows` :attr:`_engine.CursorResult.inserted_primary_key` :attr:`_engine.CursorResult.inserted_primary_key_rows` """ self._return_defaults = True self._return_defaults_columns = cols class Insert(ValuesBase): """Represent an INSERT construct. The :class:`_expression.Insert` object is created using the :func:`_expression.insert()` function. """ __visit_name__ = "insert" _supports_multi_parameters = True select = None include_insert_from_select_defaults = False is_insert = True _traverse_internals = ( [ ("table", InternalTraversal.dp_clauseelement), ("_inline", InternalTraversal.dp_boolean), ("_select_names", InternalTraversal.dp_string_list), ("_values", InternalTraversal.dp_dml_values), ("_multi_values", InternalTraversal.dp_dml_multi_values), ("select", InternalTraversal.dp_clauseelement), ("_post_values_clause", InternalTraversal.dp_clauseelement), ("_returning", InternalTraversal.dp_clauseelement_tuple), ("_hints", InternalTraversal.dp_table_hint_list), ("_return_defaults", InternalTraversal.dp_boolean), ( "_return_defaults_columns", InternalTraversal.dp_clauseelement_tuple, ), ] + HasPrefixes._has_prefixes_traverse_internals + DialectKWArgs._dialect_kwargs_traverse_internals + Executable._executable_traverse_internals + HasCTE._has_ctes_traverse_internals ) @ValuesBase._constructor_20_deprecations( "insert", "Insert", [ "values", "inline", "bind", "prefixes", "returning", "return_defaults", ], ) def __init__( self, table, values=None, inline=False, bind=None, prefixes=None, returning=None, return_defaults=False, **dialect_kw ): """Construct an :class:`_expression.Insert` object. E.g.:: from sqlalchemy import insert stmt = ( insert(user_table). values(name='username', fullname='Full Username') ) Similar functionality is available via the :meth:`_expression.TableClause.insert` method on :class:`_schema.Table`. .. seealso:: :ref:`tutorial_core_insert` - in the :ref:`unified_tutorial` :param table: :class:`_expression.TableClause` which is the subject of the insert. :param values: collection of values to be inserted; see :meth:`_expression.Insert.values` for a description of allowed formats here. Can be omitted entirely; a :class:`_expression.Insert` construct will also dynamically render the VALUES clause at execution time based on the parameters passed to :meth:`_engine.Connection.execute`. :param inline: if True, no attempt will be made to retrieve the SQL-generated default values to be provided within the statement; in particular, this allows SQL expressions to be rendered 'inline' within the statement without the need to pre-execute them beforehand; for backends that support "returning", this turns off the "implicit returning" feature for the statement. If both :paramref:`_expression.Insert.values` and compile-time bind parameters are present, the compile-time bind parameters override the information specified within :paramref:`_expression.Insert.values` on a per-key basis. The keys within :paramref:`_expression.Insert.values` can be either :class:`~sqlalchemy.schema.Column` objects or their string identifiers. Each key may reference one of: * a literal data value (i.e. string, number, etc.); * a Column object; * a SELECT statement. If a ``SELECT`` statement is specified which references this ``INSERT`` statement's table, the statement will be correlated against the ``INSERT`` statement. .. seealso:: :ref:`tutorial_core_insert` - in the :ref:`unified_tutorial` """ super(Insert, self).__init__(table, values, prefixes) self._bind = bind self._inline = inline if returning: self._returning = returning if dialect_kw: self._validate_dialect_kwargs_deprecated(dialect_kw) if return_defaults: self._return_defaults = True if not isinstance(return_defaults, bool): self._return_defaults_columns = return_defaults @_generative def inline(self): """Make this :class:`_expression.Insert` construct "inline" . When set, no attempt will be made to retrieve the SQL-generated default values to be provided within the statement; in particular, this allows SQL expressions to be rendered 'inline' within the statement without the need to pre-execute them beforehand; for backends that support "returning", this turns off the "implicit returning" feature for the statement. .. versionchanged:: 1.4 the :paramref:`_expression.Insert.inline` parameter is now superseded by the :meth:`_expression.Insert.inline` method. """ self._inline = True @_generative def from_select(self, names, select, include_defaults=True): """Return a new :class:`_expression.Insert` construct which represents an ``INSERT...FROM SELECT`` statement. e.g.:: sel = select(table1.c.a, table1.c.b).where(table1.c.c > 5) ins = table2.insert().from_select(['a', 'b'], sel) :param names: a sequence of string column names or :class:`_schema.Column` objects representing the target columns. :param select: a :func:`_expression.select` construct, :class:`_expression.FromClause` or other construct which resolves into a :class:`_expression.FromClause`, such as an ORM :class:`_query.Query` object, etc. The order of columns returned from this FROM clause should correspond to the order of columns sent as the ``names`` parameter; while this is not checked before passing along to the database, the database would normally raise an exception if these column lists don't correspond. :param include_defaults: if True, non-server default values and SQL expressions as specified on :class:`_schema.Column` objects (as documented in :ref:`metadata_defaults_toplevel`) not otherwise specified in the list of names will be rendered into the INSERT and SELECT statements, so that these values are also included in the data to be inserted. .. note:: A Python-side default that uses a Python callable function will only be invoked **once** for the whole statement, and **not per row**. .. versionadded:: 1.0.0 - :meth:`_expression.Insert.from_select` now renders Python-side and SQL expression column defaults into the SELECT statement for columns otherwise not included in the list of column names. .. versionchanged:: 1.0.0 an INSERT that uses FROM SELECT implies that the :paramref:`_expression.insert.inline` flag is set to True, indicating that the statement will not attempt to fetch the "last inserted primary key" or other defaults. The statement deals with an arbitrary number of rows, so the :attr:`_engine.CursorResult.inserted_primary_key` accessor does not apply. """ if self._values: raise exc.InvalidRequestError( "This construct already inserts value expressions" ) self._select_names = names self._inline = True self.include_insert_from_select_defaults = include_defaults self.select = coercions.expect(roles.DMLSelectRole, select) class DMLWhereBase(object): _where_criteria = () @_generative def where(self, *whereclause): """Return a new construct with the given expression(s) added to its WHERE clause, joined to the existing clause via AND, if any. Both :meth:`_dml.Update.where` and :meth:`_dml.Delete.where` support multiple-table forms, including database-specific ``UPDATE...FROM`` as well as ``DELETE..USING``. For backends that don't have multiple-table support, a backend agnostic approach to using multiple tables is to make use of correlated subqueries. See the linked tutorial sections below for examples. .. seealso:: :ref:`tutorial_correlated_updates` :ref:`tutorial_update_from` :ref:`tutorial_multi_table_deletes` """ for criterion in whereclause: where_criteria = coercions.expect(roles.WhereHavingRole, criterion) self._where_criteria += (where_criteria,) def filter(self, *criteria): """A synonym for the :meth:`_dml.DMLWhereBase.where` method. .. versionadded:: 1.4 """ return self.where(*criteria) def _filter_by_zero(self): return self.table def filter_by(self, **kwargs): r"""apply the given filtering criterion as a WHERE clause to this select. """ from_entity = self._filter_by_zero() clauses = [ _entity_namespace_key(from_entity, key) == value for key, value in kwargs.items() ] return self.filter(*clauses) @property def whereclause(self): """Return the completed WHERE clause for this :class:`.DMLWhereBase` statement. This assembles the current collection of WHERE criteria into a single :class:`_expression.BooleanClauseList` construct. .. versionadded:: 1.4 """ return BooleanClauseList._construct_for_whereclause( self._where_criteria ) class Update(DMLWhereBase, ValuesBase): """Represent an Update construct. The :class:`_expression.Update` object is created using the :func:`_expression.update()` function. """ __visit_name__ = "update" is_update = True _traverse_internals = ( [ ("table", InternalTraversal.dp_clauseelement), ("_where_criteria", InternalTraversal.dp_clauseelement_tuple), ("_inline", InternalTraversal.dp_boolean), ("_ordered_values", InternalTraversal.dp_dml_ordered_values), ("_values", InternalTraversal.dp_dml_values), ("_returning", InternalTraversal.dp_clauseelement_tuple), ("_hints", InternalTraversal.dp_table_hint_list), ("_return_defaults", InternalTraversal.dp_boolean), ( "_return_defaults_columns", InternalTraversal.dp_clauseelement_tuple, ), ] + HasPrefixes._has_prefixes_traverse_internals + DialectKWArgs._dialect_kwargs_traverse_internals + Executable._executable_traverse_internals + HasCTE._has_ctes_traverse_internals ) @ValuesBase._constructor_20_deprecations( "update", "Update", [ "whereclause", "values", "inline", "bind", "prefixes", "returning", "return_defaults", "preserve_parameter_order", ], ) def __init__( self, table, whereclause=None, values=None, inline=False, bind=None, prefixes=None, returning=None, return_defaults=False, preserve_parameter_order=False, **dialect_kw ): r"""Construct an :class:`_expression.Update` object. E.g.:: from sqlalchemy import update stmt = ( update(user_table). where(user_table.c.id == 5). values(name='user #5') ) Similar functionality is available via the :meth:`_expression.TableClause.update` method on :class:`_schema.Table`. :param table: A :class:`_schema.Table` object representing the database table to be updated. :param whereclause: Optional SQL expression describing the ``WHERE`` condition of the ``UPDATE`` statement; is equivalent to using the more modern :meth:`~Update.where()` method to specify the ``WHERE`` clause. :param values: Optional dictionary which specifies the ``SET`` conditions of the ``UPDATE``. If left as ``None``, the ``SET`` conditions are determined from those parameters passed to the statement during the execution and/or compilation of the statement. When compiled standalone without any parameters, the ``SET`` clause generates for all columns. Modern applications may prefer to use the generative :meth:`_expression.Update.values` method to set the values of the UPDATE statement. :param inline: if True, SQL defaults present on :class:`_schema.Column` objects via the ``default`` keyword will be compiled 'inline' into the statement and not pre-executed. This means that their values will not be available in the dictionary returned from :meth:`_engine.CursorResult.last_updated_params`. :param preserve_parameter_order: if True, the update statement is expected to receive parameters **only** via the :meth:`_expression.Update.values` method, and they must be passed as a Python ``list`` of 2-tuples. The rendered UPDATE statement will emit the SET clause for each referenced column maintaining this order. .. versionadded:: 1.0.10 .. seealso:: :ref:`updates_order_parameters` - illustrates the :meth:`_expression.Update.ordered_values` method. If both ``values`` and compile-time bind parameters are present, the compile-time bind parameters override the information specified within ``values`` on a per-key basis. The keys within ``values`` can be either :class:`_schema.Column` objects or their string identifiers (specifically the "key" of the :class:`_schema.Column`, normally but not necessarily equivalent to its "name"). Normally, the :class:`_schema.Column` objects used here are expected to be part of the target :class:`_schema.Table` that is the table to be updated. However when using MySQL, a multiple-table UPDATE statement can refer to columns from any of the tables referred to in the WHERE clause. The values referred to in ``values`` are typically: * a literal data value (i.e. string, number, etc.) * a SQL expression, such as a related :class:`_schema.Column`, a scalar-returning :func:`_expression.select` construct, etc. When combining :func:`_expression.select` constructs within the values clause of an :func:`_expression.update` construct, the subquery represented by the :func:`_expression.select` should be *correlated* to the parent table, that is, providing criterion which links the table inside the subquery to the outer table being updated:: users.update().values( name=select(addresses.c.email_address).\ where(addresses.c.user_id==users.c.id).\ scalar_subquery() ) .. seealso:: :ref:`inserts_and_updates` - SQL Expression Language Tutorial """ self._preserve_parameter_order = preserve_parameter_order super(Update, self).__init__(table, values, prefixes) self._bind = bind if returning: self._returning = returning if whereclause is not None: self._where_criteria += ( coercions.expect(roles.WhereHavingRole, whereclause), ) self._inline = inline if dialect_kw: self._validate_dialect_kwargs_deprecated(dialect_kw) self._return_defaults = return_defaults @_generative def ordered_values(self, *args): """Specify the VALUES clause of this UPDATE statement with an explicit parameter ordering that will be maintained in the SET clause of the resulting UPDATE statement. E.g.:: stmt = table.update().ordered_values( ("name", "ed"), ("ident": "foo") ) .. seealso:: :ref:`tutorial_parameter_ordered_updates` - full example of the :meth:`_expression.Update.ordered_values` method. .. versionchanged:: 1.4 The :meth:`_expression.Update.ordered_values` method supersedes the :paramref:`_expression.update.preserve_parameter_order` parameter, which will be removed in SQLAlchemy 2.0. """ if self._values: raise exc.ArgumentError( "This statement already has values present" ) elif self._ordered_values: raise exc.ArgumentError( "This statement already has ordered values present" ) kv_generator = DMLState.get_plugin_class(self)._get_crud_kv_pairs self._ordered_values = kv_generator(self, args) @_generative def inline(self): """Make this :class:`_expression.Update` construct "inline" . When set, SQL defaults present on :class:`_schema.Column` objects via the ``default`` keyword will be compiled 'inline' into the statement and not pre-executed. This means that their values will not be available in the dictionary returned from :meth:`_engine.CursorResult.last_updated_params`. .. versionchanged:: 1.4 the :paramref:`_expression.update.inline` parameter is now superseded by the :meth:`_expression.Update.inline` method. """ self._inline = True class Delete(DMLWhereBase, UpdateBase): """Represent a DELETE construct. The :class:`_expression.Delete` object is created using the :func:`_expression.delete()` function. """ __visit_name__ = "delete" is_delete = True _traverse_internals = ( [ ("table", InternalTraversal.dp_clauseelement), ("_where_criteria", InternalTraversal.dp_clauseelement_tuple), ("_returning", InternalTraversal.dp_clauseelement_tuple), ("_hints", InternalTraversal.dp_table_hint_list), ] + HasPrefixes._has_prefixes_traverse_internals + DialectKWArgs._dialect_kwargs_traverse_internals + Executable._executable_traverse_internals + HasCTE._has_ctes_traverse_internals ) @ValuesBase._constructor_20_deprecations( "delete", "Delete", ["whereclause", "values", "bind", "prefixes", "returning"], ) def __init__( self, table, whereclause=None, bind=None, returning=None, prefixes=None, **dialect_kw ): r"""Construct :class:`_expression.Delete` object. E.g.:: from sqlalchemy import delete stmt = ( delete(user_table). where(user_table.c.id == 5) ) Similar functionality is available via the :meth:`_expression.TableClause.delete` method on :class:`_schema.Table`. .. seealso:: :ref:`inserts_and_updates` - in the :ref:`1.x tutorial <sqlexpression_toplevel>` :ref:`tutorial_core_update_delete` - in the :ref:`unified_tutorial` :param table: The table to delete rows from. :param whereclause: Optional SQL expression describing the ``WHERE`` condition of the ``DELETE`` statement; is equivalent to using the more modern :meth:`~Delete.where()` method to specify the ``WHERE`` clause. .. seealso:: :ref:`deletes` - SQL Expression Tutorial """ self._bind = bind self.table = coercions.expect( roles.DMLTableRole, table, apply_propagate_attrs=self ) if returning: self._returning = returning if prefixes: self._setup_prefixes(prefixes) if whereclause is not None: self._where_criteria += ( coercions.expect(roles.WhereHavingRole, whereclause), ) if dialect_kw: self._validate_dialect_kwargs_deprecated(dialect_kw)