Don't create a new MetaData in LazyMapperCollection,

but use the one created in the wrapper.
In some cases, you could have some tables in the metadata created in the wrapper,
and some tables in the metadata created in the LazyMapperCollection,
which gave an error when trying to create relations.

CHANGES.txt

@@ -1,6 +1,12 @@
 1.3.11 (unreleased)
 -------------------
 
+- Don't create a new MetaData in LazyMapperCollection,
+  but use the one created in the wrapper.
+  In some cases, you could have some tables in the metadata created in the wrapper,
+  and some tables in the metadata created in the LazyMapperCollection,
+  which gave an error when trying to create relations.
+
 - When generating the mapper class, make sure table.name is a string.
   It can be unicode when use_unicode=1 with MySQL engine.
 

src/z3c/sqlalchemy/mapper.py

@@ -14,7 +14,7 @@
 import new
 import threading
 
-from sqlalchemy import Table, MetaData 
+from sqlalchemy import Table 
 from sqlalchemy.orm import mapper, relation, class_mapper
 from sqlalchemy.ext.declarative import DeclarativeMeta
 
@@ -131,7 +131,7 @@ def __init__(self, wrapper):
         self._wrapper = wrapper
         self._engine = wrapper.engine
         self._model = wrapper.model or {}
-        self._metadata = MetaData(self._engine)
+        self._metadata = wrapper.metadata
         self._mapper_factory = MapperFactory(self._metadata)
         self._dependent_tables = None
         self._lock = threading.Lock()