diff options
Diffstat (limited to 'lib/sqlalchemy/engine/result.py')
| -rw-r--r-- | lib/sqlalchemy/engine/result.py | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/lib/sqlalchemy/engine/result.py b/lib/sqlalchemy/engine/result.py index ac033a5ae..986edd617 100644 --- a/lib/sqlalchemy/engine/result.py +++ b/lib/sqlalchemy/engine/result.py @@ -114,6 +114,44 @@ class CursorResultMetaData(ResultMetaData): "keys", ) + def _adapt_to_context(self, context): + """When using a cached result metadata against a new context, + we need to rewrite the _keymap so that it has the specific + Column objects in the new context inside of it. this accommodates + for select() constructs that contain anonymized columns and + are cached. + + """ + if not context.compiled._result_columns: + return self + + compiled_statement = context.compiled.statement + invoked_statement = context.invoked_statement + + # same statement was invoked as the one we cached against, + # return self + if compiled_statement is invoked_statement: + return self + + # make a copy and add the columns from the invoked statement + # to the result map. + md = self.__class__.__new__(self.__class__) + + md._keymap = self._keymap.copy() + + # match up new columns positionally to the result columns + for existing, new in zip( + context.compiled._result_columns, + invoked_statement._exported_columns_iterator(), + ): + md._keymap[new] = md._keymap[existing[RM_NAME]] + + md.case_sensitive = self.case_sensitive + md.matched_on_name = self.matched_on_name + md._processors = self._processors + md.keys = self.keys + return md + def __init__(self, parent, cursor_description): context = parent.context dialect = context.dialect @@ -1107,7 +1145,9 @@ class BaseResult(object): if strat.cursor_description is not None: if self.context.compiled: if self.context.compiled._cached_metadata: - self._metadata = self.context.compiled._cached_metadata + cached_md = self.context.compiled._cached_metadata + self._metadata = cached_md._adapt_to_context(self.context) + else: self._metadata = ( self.context.compiled._cached_metadata |