- A large refactoring of the ``sqlalchemy.sql`` package has reorganized

the import structure of many core modules.
``sqlalchemy.schema`` and ``sqlalchemy.types``
remain in the top-level package, but are now just lists of names
that pull from within ``sqlalchemy.sql``.  Their implementations
are now broken out among ``sqlalchemy.sql.type_api``, ``sqlalchemy.sql.sqltypes``,
``sqlalchemy.sql.schema`` and ``sqlalchemy.sql.ddl``, the last of which was
moved from ``sqlalchemy.engine``.  ``sqlalchemy.sql.expression`` is also
a namespace now which pulls implementations mostly from ``sqlalchemy.sql.elements``,
``sqlalchemy.sql.selectable``, and ``sqlalchemy.sql.dml``.
Most of the "factory" functions
used to create SQL expression objects have been moved to classmethods
or constructors, which are exposed in ``sqlalchemy.sql.expression``
using a programmatic system.  Care has been taken such that all the
original import namespaces remain intact and there should be no impact
on any existing applications.   The rationale here was to break out these
very large modules into smaller ones, provide more manageable lists
of function names, to greatly reduce "import cycles" and clarify the
up-front importing of names, and to remove the need for redundant
functions and documentation throughout the expression package.

1 files changed, 668 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/dml.py b/lib/sqlalchemy/sql/dml.py
new file mode 100644
index 000000000..cd06bf21a
--- /dev/null
+++ b/lib/sqlalchemy/sql/dml.py
@@ -0,0 +1,668 @@
+# schema/dml.py
+# Copyright (C) 2009-2013 the SQLAlchemy authors and contributors <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: http://www.opensource.org/licenses/mit-license.php
+"""
+Provide :class:`.Insert`, :class:`.Update` and :class:`.Delete`.
+
+"""
+
+from .base import Executable, _generative, _from_objects
+from .elements import ClauseElement, _literal_as_text, Null, and_, _clone
+from .selectable import _interpret_as_from, _interpret_as_select, HasPrefixes
+from .. import util
+from .. import exc
+
+class UpdateBase(HasPrefixes, Executable, ClauseElement):
+    """Form the base for ``INSERT``, ``UPDATE``, and ``DELETE`` statements.
+
+    """
+
+    __visit_name__ = 'update_base'
+
+    _execution_options = \
+        Executable._execution_options.union({'autocommit': True})
+    kwargs = util.immutabledict()
+    _hints = util.immutabledict()
+    _prefixes = ()
+
+    def _process_colparams(self, parameters):
+        def process_single(p):
+            if isinstance(p, (list, tuple)):
+                return dict(
+                    (c.key, pval)
+                    for c, pval in zip(self.table.c, p)
+                )
+            else:
+                return p
+
+        if isinstance(parameters, (list, tuple)) and \
+              isinstance(parameters[0], (list, tuple, dict)):
+
+            if not self._supports_multi_parameters:
+                raise exc.InvalidRequestError(
+                    "This construct does not support "
+                    "multiple parameter sets.")
+
+            return [process_single(p) for p in parameters], True
+        else:
+            return process_single(parameters), False
+
+    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).")
+
+    def bind(self):
+        """Return a 'bind' linked to this :class:`.UpdateBase`
+        or a :class:`.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):
+        """Add a RETURNING or equivalent clause to this statement.
+
+        The given list of columns represent columns within the table that is
+        the target of the INSERT, UPDATE, or DELETE. Each element can be any
+        column expression. :class:`~sqlalchemy.schema.Table` objects will be
+        expanded into their individual columns.
+
+        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 ``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.
+
+        """
+        self._returning = cols
+
+    @_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:`.Table` that is the subject of this
+        statement, or optionally to that of the given
+        :class:`.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")
+
+        .. versionadded:: 0.7.6
+
+        :param text: Text of the hint.
+        :param selectable: optional :class:`.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})
+
+
+class ValuesBase(UpdateBase):
+    """Supplies support for :meth:`.ValuesBase.values` to
+    INSERT and UPDATE constructs."""
+
+    __visit_name__ = 'values_base'
+
+    _supports_multi_parameters = False
+    _has_multi_parameters = False
+    select = None
+
+    def __init__(self, table, values, prefixes):
+        self.table = _interpret_as_from(table)
+        self.parameters, self._has_multi_parameters = \
+                            self._process_colparams(values)
+        if prefixes:
+            self._setup_prefixes(prefixes)
+
+    @_generative
+    def values(self, *args, **kwargs):
+        """specify a fixed VALUES clause for an INSERT statement, or the SET
+        clause for an UPDATE.
+
+        Note that the :class:`.Insert` and :class:`.Update` constructs support
+        per-execution time formatting of the VALUES and/or SET clauses,
+        based on the arguments passed to :meth:`.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:`.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: Alternatively, 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 single dictionary form
+         works the same as the kwargs form::
+
+            users.insert().values({"name": "some name"})
+
+         If a tuple is passed, the tuple should contain the same number
+         of columns as the target :class:`.Table`::
+
+            users.insert().values((5, "some name"))
+
+         The :class:`.Insert` construct also supports multiply-rendered VALUES
+         construct, for those backends which support this SQL syntax
+         (SQLite, Postgresql, MySQL).  This mode is indicated by passing a list
+         of one or more dictionaries/tuples::
+
+            users.insert().values([
+                                {"name": "some name"},
+                                {"name": "some other name"},
+                                {"name": "yet another name"},
+                            ])
+
+         In the case of an :class:`.Update`
+         construct, only the single dictionary/tuple form is accepted,
+         else an exception is raised.  It is also an exception case to
+         attempt to mix the single-/multiple- value styles together,
+         either through multiple :meth:`.ValuesBase.values` calls
+         or by sending a list + kwargs at the same time.
+
+         .. note::
+
+             Passing a multiple values list is *not* the same
+             as passing a multiple values list to the :meth:`.Connection.execute`
+             method.  Passing a list of parameter sets to :meth:`.ValuesBase.values`
+             produces a construct of this form::
+
+                INSERT INTO table (col1, col2, col3) VALUES
+                                (col1_0, col2_0, col3_0),
+                                (col1_1, col2_1, col3_1),
+                                ...
+
+             whereas a multiple list passed to :meth:`.Connection.execute`
+             has the effect of using the DBAPI
+             `executemany() <http://www.python.org/dev/peps/pep-0249/#id18>`_
+             method, which provides a high-performance system of invoking
+             a single-row INSERT statement many times against a series
+             of parameter sets.   The "executemany" style is supported by
+             all database backends, as it does not depend on a special SQL
+             syntax.
+
+         .. versionadded:: 0.8
+             Support for multiple-VALUES INSERT statements.
+
+
+        .. seealso::
+
+            :ref:`inserts_and_updates` - SQL Expression
+            Language Tutorial
+
+            :func:`~.expression.insert` - produce an ``INSERT`` statement
+
+            :func:`~.expression.update` - produce an ``UPDATE`` statement
+
+        """
+        if self.select is not None:
+            raise exc.InvalidRequestError(
+                        "This construct already inserts from a SELECT")
+        if self._has_multi_parameters and kwargs:
+            raise exc.InvalidRequestError(
+                        "This construct already has multiple parameter sets.")
+
+        if args:
+            if len(args) > 1:
+                raise exc.ArgumentError(
+                            "Only a single dictionary/tuple or list of "
+                            "dictionaries/tuples is accepted positionally.")
+            v = args[0]
+        else:
+            v = {}
+
+        if self.parameters is None:
+            self.parameters, self._has_multi_parameters = \
+                    self._process_colparams(v)
+        else:
+            if self._has_multi_parameters:
+                self.parameters = list(self.parameters)
+                p, self._has_multi_parameters = self._process_colparams(v)
+                if not self._has_multi_parameters:
+                    raise exc.ArgumentError(
+                        "Can't mix single-values and multiple values "
+                        "formats in one statement")
+
+                self.parameters.extend(p)
+            else:
+                self.parameters = self.parameters.copy()
+                p, self._has_multi_parameters = self._process_colparams(v)
+                if self._has_multi_parameters:
+                    raise exc.ArgumentError(
+                        "Can't mix single-values and multiple values "
+                        "formats in one statement")
+                self.parameters.update(p)
+
+        if kwargs:
+            if self._has_multi_parameters:
+                raise exc.ArgumentError(
+                            "Can't pass kwargs and multiple parameter sets "
+                            "simultaenously")
+            else:
+                self.parameters.update(kwargs)
+
+
+class Insert(ValuesBase):
+    """Represent an INSERT construct.
+
+    The :class:`.Insert` object is created using the
+    :func:`~.expression.insert()` function.
+
+    .. seealso::
+
+        :ref:`coretutorial_insert_expressions`
+
+    """
+    __visit_name__ = 'insert'
+
+    _supports_multi_parameters = True
+
+    def __init__(self,
+                table,
+                values=None,
+                inline=False,
+                bind=None,
+                prefixes=None,
+                returning=None,
+                **kwargs):
+        """Construct an :class:`.Insert` object.
+
+        Similar functionality is available via the
+        :meth:`~.TableClause.insert` method on
+        :class:`~.schema.Table`.
+
+        :param table: :class:`.TableClause` which is the subject of the insert.
+
+        :param values: collection of values to be inserted; see
+         :meth:`.Insert.values` for a description of allowed formats here.
+         Can be omitted entirely; a :class:`.Insert` construct will also
+         dynamically render the VALUES clause at execution time based on
+         the parameters passed to :meth:`.Connection.execute`.
+
+        :param inline: if True, SQL defaults will be compiled 'inline' into the
+          statement and not pre-executed.
+
+        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:`~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:`coretutorial_insert_expressions` - SQL Expression Tutorial
+
+            :ref:`inserts_and_updates` - SQL Expression Tutorial
+
+        """
+        ValuesBase.__init__(self, table, values, prefixes)
+        self._bind = bind
+        self.select = None
+        self.inline = inline
+        self._returning = returning
+        self.kwargs = kwargs
+
+    def get_children(self, **kwargs):
+        if self.select is not None:
+            return self.select,
+        else:
+            return ()
+
+    @_generative
+    def from_select(self, names, select):
+        """Return a new :class:`.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:`.Column`
+         objects representing the target columns.
+        :param select: a :func:`.select` construct, :class:`.FromClause`
+         or other construct which resolves into a :class:`.FromClause`,
+         such as an ORM :class:`.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.
+
+        .. note::
+
+           Depending on backend, it may be necessary for the :class:`.Insert`
+           statement to be constructed using the ``inline=True`` flag; this
+           flag will prevent the implicit usage of ``RETURNING`` when the
+           ``INSERT`` statement is rendered, which isn't supported on a backend
+           such as Oracle in conjunction with an ``INSERT..SELECT`` combination::
+
+             sel = select([table1.c.a, table1.c.b]).where(table1.c.c > 5)
+             ins = table2.insert(inline=True).from_select(['a', 'b'], sel)
+
+        .. versionadded:: 0.8.3
+
+        """
+        if self.parameters:
+            raise exc.InvalidRequestError(
+                        "This construct already inserts value expressions")
+
+        self.parameters, self._has_multi_parameters = \
+                self._process_colparams(dict((n, Null()) for n in names))
+
+        self.select = _interpret_as_select(select)
+
+    def _copy_internals(self, clone=_clone, **kw):
+        # TODO: coverage
+        self.parameters = self.parameters.copy()
+        if self.select is not None:
+            self.select = _clone(self.select)
+
+
+class Update(ValuesBase):
+    """Represent an Update construct.
+
+    The :class:`.Update` object is created using the :func:`update()` function.
+
+    """
+    __visit_name__ = 'update'
+
+    def __init__(self,
+                table,
+                whereclause=None,
+                values=None,
+                inline=False,
+                bind=None,
+                prefixes=None,
+                returning=None,
+                **kwargs):
+        """Construct an :class:`.Update` object.
+
+        E.g.::
+
+            from sqlalchemy import update
+
+            stmt = update(users).where(users.c.id==5).\\
+                    values(name='user #5')
+
+        Similar functionality is available via the
+        :meth:`~.TableClause.update` method on
+        :class:`.Table`::
+
+            stmt = users.update().\\
+                        where(users.c.id==5).\\
+                        values(name='user #5')
+
+        :param table: A :class:`.Table` object representing the database
+         table to be updated.
+
+        :param whereclause: Optional SQL expression describing the ``WHERE``
+         condition of the ``UPDATE`` statement.   Modern applications
+         may prefer to use the generative :meth:`~Update.where()`
+         method to specify the ``WHERE`` clause.
+
+         The WHERE clause can refer to multiple tables.
+         For databases which support this, an ``UPDATE FROM`` clause will
+         be generated, or on MySQL, a multi-table update.  The statement
+         will fail on databases that don't have support for multi-table
+         update statements.  A SQL-standard method of referring to
+         additional tables in the WHERE clause is to use a correlated
+         subquery::
+
+            users.update().values(name='ed').where(
+                    users.c.name==select([addresses.c.email_address]).\\
+                                where(addresses.c.user_id==users.c.id).\\
+                                as_scalar()
+                    )
+
+         .. versionchanged:: 0.7.4
+             The WHERE clause can refer to multiple tables.
+
+        :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:`.Update.values` method to set the values of the
+          UPDATE statement.
+
+        :param inline:
+          if True, SQL defaults present on :class:`.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:`.ResultProxy.last_updated_params`.
+
+        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:`.Column`
+        objects or their string identifiers (specifically the "key" of the
+        :class:`.Column`, normally but not necessarily equivalent to
+        its "name").  Normally, the
+        :class:`.Column` objects used here are expected to be
+        part of the target :class:`.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:`.Column`,
+          a scalar-returning :func:`.select` construct,
+          etc.
+
+        When combining :func:`.select` constructs within the values
+        clause of an :func:`.update` construct,
+        the subquery represented by the :func:`.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).\\
+                            as_scalar()
+                )
+
+        .. seealso::
+
+            :ref:`inserts_and_updates` - SQL Expression
+            Language Tutorial
+
+
+        """
+        ValuesBase.__init__(self, table, values, prefixes)
+        self._bind = bind
+        self._returning = returning
+        if whereclause is not None:
+            self._whereclause = _literal_as_text(whereclause)
+        else:
+            self._whereclause = None
+        self.inline = inline
+        self.kwargs = kwargs
+
+
+    def get_children(self, **kwargs):
+        if self._whereclause is not None:
+            return self._whereclause,
+        else:
+            return ()
+
+    def _copy_internals(self, clone=_clone, **kw):
+        # TODO: coverage
+        self._whereclause = clone(self._whereclause, **kw)
+        self.parameters = self.parameters.copy()
+
+    @_generative
+    def where(self, whereclause):
+        """return a new update() construct with the given expression added to
+        its WHERE clause, joined to the existing clause via AND, if any.
+
+        """
+        if self._whereclause is not None:
+            self._whereclause = and_(self._whereclause,
+                    _literal_as_text(whereclause))
+        else:
+            self._whereclause = _literal_as_text(whereclause)
+
+    @property
+    def _extra_froms(self):
+        # TODO: this could be made memoized
+        # if the memoization is reset on each generative call.
+        froms = []
+        seen = set([self.table])
+
+        if self._whereclause is not None:
+            for item in _from_objects(self._whereclause):
+                if not seen.intersection(item._cloned_set):
+                    froms.append(item)
+                seen.update(item._cloned_set)
+
+        return froms
+
+
+class Delete(UpdateBase):
+    """Represent a DELETE construct.
+
+    The :class:`.Delete` object is created using the :func:`delete()` function.
+
+    """
+
+    __visit_name__ = 'delete'
+
+    def __init__(self,
+            table,
+            whereclause=None,
+            bind=None,
+            returning=None,
+            prefixes=None,
+            **kwargs):
+        """Construct :class:`.Delete` object.
+
+        Similar functionality is available via the
+        :meth:`~.TableClause.delete` method on
+        :class:`~.schema.Table`.
+
+        :param table: The table to be updated.
+
+        :param whereclause: A :class:`.ClauseElement` describing the ``WHERE``
+          condition of the ``UPDATE`` statement. Note that the
+          :meth:`~Delete.where()` generative method may be used instead.
+
+        .. seealso::
+
+            :ref:`deletes` - SQL Expression Tutorial
+
+        """
+        self._bind = bind
+        self.table = _interpret_as_from(table)
+        self._returning = returning
+
+        if prefixes:
+            self._setup_prefixes(prefixes)
+
+        if whereclause is not None:
+            self._whereclause = _literal_as_text(whereclause)
+        else:
+            self._whereclause = None
+
+        self.kwargs = kwargs
+
+    def get_children(self, **kwargs):
+        if self._whereclause is not None:
+            return self._whereclause,
+        else:
+            return ()
+
+    @_generative
+    def where(self, whereclause):
+        """Add the given WHERE clause to a newly returned delete construct."""
+
+        if self._whereclause is not None:
+            self._whereclause = and_(self._whereclause,
+                    _literal_as_text(whereclause))
+        else:
+            self._whereclause = _literal_as_text(whereclause)
+
+    def _copy_internals(self, clone=_clone, **kw):
+        # TODO: coverage
+        self._whereclause = clone(self._whereclause, **kw)
+