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from ...sql.elements import ClauseElement
from ...sql.dml import Insert as StandardInsert
from ...sql.expression import alias
from ...util.langhelpers import public_factory
from ...sql.base import _generative
from ... import util
__all__ = ('Insert', 'insert')
class Insert(StandardInsert):
"""MySQL-specific implementation of INSERT.
Adds methods for MySQL-specific syntaxes such as ON DUPLICATE KEY UPDATE.
.. versionadded:: 1.2
"""
@property
def inserted(self):
"""Provide the "inserted" namespace for an ON DUPLICATE KEY UPDATE statement
MySQL's ON DUPLICATE KEY UPDATE clause allows reference to the row
that would be inserted, via a special function called ``VALUES()``.
This attribute provides all columns in this row to be referenaceable
such that they will render within a ``VALUES()`` function inside the
ON DUPLICATE KEY UPDATE clause. The attribute is named ``.inserted``
so as not to conflict with the existing :meth:`.Insert.values` method.
.. seealso::
:ref:`mysql_insert_on_duplicate_key_update` - example of how
to use :attr:`.Insert.inserted`
"""
return self.inserted_alias.columns
@util.memoized_property
def inserted_alias(self):
return alias(self.table, name='inserted')
@_generative
def on_duplicate_key_update(self, **kw):
r"""
Specifies the ON DUPLICATE KEY UPDATE clause.
:param \**kw: Column keys linked to UPDATE values. The
values may be any SQL expression or supported literal Python
values.
.. warning:: This dictionary does **not** take into account
Python-specified default UPDATE values or generation functions,
e.g. those specified using :paramref:`.Column.onupdate`.
These values will not be exercised for an ON DUPLICATE KEY UPDATE
style of UPDATE, unless values are manually specified here.
.. versionadded:: 1.2
.. seealso::
:ref:`mysql_insert_on_duplicate_key_update`
"""
inserted_alias = getattr(self, 'inserted_alias', None)
self._post_values_clause = OnDuplicateClause(inserted_alias, kw)
return self
insert = public_factory(Insert, '.dialects.mysql.insert')
class OnDuplicateClause(ClauseElement):
__visit_name__ = 'on_duplicate_key_update'
def __init__(self, inserted_alias, update):
self.inserted_alias = inserted_alias
if not update or not isinstance(update, dict):
raise ValueError('update parameter must be a non-empty dictionary')
self.update = update
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