Django

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Changeset 9272

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Timestamp:
10/24/08 04:36:22 (3 months ago)
Author:
mtredinnick
Message:

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.

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  • django/trunk/django/db/backends/oracle/query.py

    r9235 r9272  
    2626 
    2727    class OracleQuery(QueryClass): 
     28        def __reduce__(self): 
     29            """ 
     30            Enable pickling for this class (normal pickling handling doesn't 
     31            work as Python can only pickle module-level classes by default). 
     32            """ 
     33            if hasattr(QueryClass, '__getstate__'): 
     34                assert hasattr(QueryClass, '__setstate__') 
     35                data = self.__getstate__() 
     36            else: 
     37                data = self.__dict__ 
     38            return (unpickle_query_class, (QueryClass,), data) 
     39 
    2840        def resolve_columns(self, row, fields=()): 
    2941            # If this query has limit/offset information, then we expect the 
    …… 
    121133    _classes[QueryClass] = OracleQuery 
    122134    return OracleQuery 
     135 
     136def unpickle_query_class(QueryClass): 
     137    """ 
     138    Utility function, called by Python's unpickling machinery, that handles 
     139    unpickling of Oracle Query subclasses. 
     140    """ 
     141    # XXX: Would be nice to not have any dependency on cx_Oracle here. Since 
     142    # modules can't be pickled, we need a way to know to load the right module. 
     143    import cx_Oracle 
     144 
     145    klass = query_class(QueryClass, cx_Oracle) 
     146    return klass.__new__(klass) 
     147unpickle_query_class.__safe_for_unpickling__ = True 
     148 

  • django/trunk/django/db/models/sql/query.py

    r9251 r9272  
    2828    from sets import Set as set     # Python 2.3 fallback 
    2929 
    30 __all__ = ['Query'] 
    31  
    32 class Query(object): 
     30__all__ = ['Query', 'BaseQuery'] 
     31 
     32class BaseQuery(object): 
    3333    """ 
    3434    A single SQL query. 
    …… 
    17581758# default. 
    17591759if connection.features.uses_custom_query_class: 
    1760     Query = connection.ops.query_class(Query) 
     1760    Query = connection.ops.query_class(BaseQuery) 
     1761else: 
     1762    Query = BaseQuery 
    17611763 
    17621764def get_order_dir(field, default='ASC'):