Commit 74c799d2 authored by Malcolm Tredinnick's avatar Malcolm Tredinnick
Browse files

[1.0.X] Fixed #9307 -- Added the ability to pickle the Query class used by the 

Oracle backend.

This allows Querysets to be cached for Oracle and should provide a model for
adding pickling support to other (external) database backends that need a
custom Query class.

Thanks to Justin Bronn for some assistance with this patch.

Backport of r9272 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9273 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent 0a1aafa5

django/db/backends/oracle/query.py

+26 −0
Original line number Diff line number Diff line
@@ -25,6 +25,18 @@ def query_class(QueryClass, Database): 
        pass



    class OracleQuery(QueryClass):

        def __reduce__(self):

            """

            Enable pickling for this class (normal pickling handling doesn't

            work as Python can only pickle module-level classes by default).

            """

            if hasattr(QueryClass, '__getstate__'):

                assert hasattr(QueryClass, '__setstate__')

                data = self.__getstate__()

            else:

                data = self.__dict__

            return (unpickle_query_class, (QueryClass,), data)



        def resolve_columns(self, row, fields=()):

            # If this query has limit/offset information, then we expect the

            # first column to be an extra "_RN" column that we need to throw
@@ -120,3 +132,17 @@ def query_class(QueryClass, Database): 


    _classes[QueryClass] = OracleQuery

    return OracleQuery



def unpickle_query_class(QueryClass):

    """

    Utility function, called by Python's unpickling machinery, that handles

    unpickling of Oracle Query subclasses.

    """

    # XXX: Would be nice to not have any dependency on cx_Oracle here. Since

    # modules can't be pickled, we need a way to know to load the right module.

    import cx_Oracle



    klass = query_class(QueryClass, cx_Oracle)

    return klass.__new__(klass)

unpickle_query_class.__safe_for_unpickling__ = True

django/db/models/sql/query.py

+5 −3
Original line number Diff line number Diff line
@@ -27,9 +27,9 @@ try: 
except NameError:

    from sets import Set as set     # Python 2.3 fallback



__all__ = ['Query']

__all__ = ['Query', 'BaseQuery']



class Query(object):

class BaseQuery(object):

    """

    A single SQL query.

    """
@@ -1757,7 +1757,9 @@ class Query(object): 
# Use the backend's custom Query class if it defines one. Otherwise, use the

# default.

if connection.features.uses_custom_query_class:

    Query = connection.ops.query_class(Query)

    Query = connection.ops.query_class(BaseQuery)

else:

    Query = BaseQuery



def get_order_dir(field, default='ASC'):

    """