From: Jonathan LaCour <jonathan@cleverdevil.org>
Date: Thu, 20 Apr 2006 21:04:03 +0000 (+0000)
Subject: Updates to ActiveMapper contributed by Gabriel Jacobo.  The main purpose of the
X-Git-Tag: rel_0_1_7~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=333a0f84b7d28397de90392b1c48a8239a6b4167;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

Updates to ActiveMapper contributed by Gabriel Jacobo.  The main purpose of the
changes is to ensure that relationships are properly detected and built in the
proper order.  This should fix some problems that people were having with
ActiveMapper requiring classes to be declared in a specific order.
---

diff --git a/lib/sqlalchemy/ext/activemapper.py b/lib/sqlalchemy/ext/activemapper.py
index 2564373e50..4b2b9055a8 100644
--- a/lib/sqlalchemy/ext/activemapper.py
+++ b/lib/sqlalchemy/ext/activemapper.py
@@ -65,15 +65,44 @@ class many_to_many(relationship):
 # 
 
 __deferred_classes__  = []
-def process_relationships(klass, was_deferred=False):
+__processed_classes__ = []
+
+def check_relationships(klass):
+    #Check the class for foreign_keys recursively. If some foreign table is not found, the processing of the table
+    #must be defered.
+    for keyname in klass.table._foreign_keys:
+        xtable = keyname._colspec[:keyname._colspec.find('.')]
+        tablefound = False
+        for xclass in ActiveMapperMeta.classes:
+            if ActiveMapperMeta.classes[xclass].table.from_name == xtable:
+                tablefound = True
+                break
+        if tablefound==False:
+            #The refered table has not yet been created.
+            return False
+
+    return True
+
+
+def process_relationships(klass):
     defer = False
     for propname, reldesc in klass.relations.items():
-        if not reldesc.classname in ActiveMapperMeta.classes:
-            if not was_deferred: __deferred_classes__.append(klass)
+        #We require that every related table has been processed first
+        if not reldesc.classname in __processed_classes__:
+            if not klass._classname in __deferred_classes__: __deferred_classes__.append(klass._classname)
             defer = True
-    
+
+
+    #Check every column item to see if it points to an existing table
+    #if it does not, defer...
+    if not defer:
+            if not check_relationships(klass):
+                if not klass._classname in __deferred_classes__: __deferred_classes__.append(klass._classname)
+                defer = True
+
     if not defer:
         relations = {}
+        __processed_classes__.append(klass._classname)
         for propname, reldesc in klass.relations.items():
             relclass = ActiveMapperMeta.classes[reldesc.classname]
             relations[propname] = relation(relclass.mapper,
@@ -82,38 +111,39 @@ def process_relationships(klass, was_deferred=False):
                                            private=reldesc.private, 
                                            lazy=reldesc.lazy, 
                                            uselist=reldesc.uselist)
-        assign_mapper(klass, klass.table, properties=relations,
-                      inherits=getattr(klass, "_base_mapper", None))
-        if was_deferred: __deferred_classes__.remove(klass)
-    
-    if not was_deferred:
+        if len(relations)>0:
+            assign_mapper(klass, klass.table, properties=relations)
+
+        if klass._classname in __deferred_classes__: __deferred_classes__.remove(klass._classname)
+
         for deferred_class in __deferred_classes__:
-            process_relationships(deferred_class, was_deferred=True)
+            process_relationships(ActiveMapperMeta.classes[deferred_class])
+
 
 
 
 class ActiveMapperMeta(type):
     classes = {}
-    
+
     def __init__(cls, clsname, bases, dict):
         table_name = clsname.lower()
         columns    = []
         relations  = {}
         _engine    = getattr( sys.modules[cls.__module__], "__engine__", engine )
-        
+
         if 'mapping' in dict:
             members = inspect.getmembers(dict.get('mapping'))
             for name, value in members:
                 if name == '__table__':
                     table_name = value
                     continue
-                
+
                 if '__engine__' == name:
                     _engine= value
                     continue
-                    
+
                 if name.startswith('__'): continue
-                
+
                 if isinstance(value, column):
                     if value.foreign_key:
                         col = Column(value.colname or name, 
@@ -128,7 +158,7 @@ class ActiveMapperMeta(type):
                                      *value.args, **value.kwargs)
                     columns.append(col)
                     continue
-                
+
                 if isinstance(value, relationship):
                     relations[name] = value
             assert _engine is not None, "No engine specified"
@@ -140,16 +170,16 @@ class ActiveMapperMeta(type):
             else:
                 assign_mapper(cls, cls.table)
             cls.relations = relations
+            cls._classname = clsname
             ActiveMapperMeta.classes[clsname] = cls
-            
             process_relationships(cls)
-        
+
         super(ActiveMapperMeta, cls).__init__(clsname, bases, dict)
 
 
 class ActiveMapper(object):
     __metaclass__ = ActiveMapperMeta
-    
+
     def set(self, **kwargs):
         for key, value in kwargs.items():
             setattr(self, key, value)
@@ -161,5 +191,4 @@ class ActiveMapper(object):
 
 def create_tables():
     for klass in ActiveMapperMeta.classes.values():
-        klass.table.create()
-
+        klass.table.create()
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