diff options
Diffstat (limited to 'lib/sqlalchemy/orm/strategies.py')
| -rw-r--r-- | lib/sqlalchemy/orm/strategies.py | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/lib/sqlalchemy/orm/strategies.py b/lib/sqlalchemy/orm/strategies.py index f46ffc44d..dc64b283d 100644 --- a/lib/sqlalchemy/orm/strategies.py +++ b/lib/sqlalchemy/orm/strategies.py @@ -660,18 +660,26 @@ class EagerLoader(AbstractRelationLoader): if entity in context.eager_joins: entity_key, default_towrap = entity, entity.selectable - elif should_nest_selectable or not context.from_clause or not sql_util.search(context.from_clause, entity.selectable): - # if no from_clause, or a from_clause we can't join to, or a subquery is going to be generated, + + elif should_nest_selectable or not context.from_clause: + # if no from_clause, or a subquery is going to be generated, # store eager joins per _MappedEntity; Query._compile_context will # add them as separate selectables to the select(), or splice them together # after the subquery is generated entity_key, default_towrap = entity, entity.selectable else: - # otherwise, create a single eager join from the from clause. - # Query._compile_context will adapt as needed and append to the - # FROM clause of the select(). - entity_key, default_towrap = None, context.from_clause - + index, clause = sql_util.find_join_source(context.from_clause, entity.selectable) + if clause: + # join to an existing FROM clause on the query. + # key it to its list index in the eager_joins dict. + # Query._compile_context will adapt as needed and append to the + # FROM clause of the select(). + entity_key, default_towrap = index, clause + else: + # if no from_clause to join to, + # store eager joins per _MappedEntity + entity_key, default_towrap = entity, entity.selectable + towrap = context.eager_joins.setdefault(entity_key, default_towrap) # create AliasedClauses object to build up the eager query. |