Changeset 144

Timestamp:

07/05/07 10:48:39 (6 years ago)

Author:

ged

Message:

- Changed the order of relationship kwargs processing so that computed kwargs

can be overridden by kwargs manually passed to the statement. This should
only be used if you know what you are doing.

- Made inverse relationships use backrefs. This fixes the "bidirectional

coherency" problem some people had before doing a flush. (based on a patch
from Remi Jolin). Added corresponding test.

Location:

elixir/trunk

Files:

• CHANGES (modified) (1 diff)
• elixir/relationships.py (modified) (13 diffs)
• tests/test_movies.py (modified) (1 diff)

elixir/trunk/CHANGES

@@ -15 +15 @@
   the method level and module level) anymore. Uses nosetest's module level 
   fixture.
-- Fixed some buggy tests.
+- Changed the order of relationship kwargs processing so that computed kwargs
+  can be overridden by kwargs manually passed to the statement. This should
+  only be used if you know what you are doing.
 - Applied patch from Ants Aasma to make Elixir compatible with the 0.4 branch
   of SQLAlchemy.
+- Fixed some buggy tests.
 - Fixed relationships to tables using a schema (Patch by Neil Blakey-Milner)
+- Made inverse relationships use backrefs. This fixes the "bidirectional
+  coherency" problem some people had before doing a flush. (based on a patch 
+  from Remi Jolin).
 
 0.3.0 - 2007-03-27

elixir/trunk/elixir/relationships.py

@@ -192 +192 @@
 from sqlalchemy         import ForeignKeyConstraint, Column, \
                                Table, and_
-from sqlalchemy.orm     import relation
+from sqlalchemy.orm     import relation, backref
 from elixir.statements  import Statement
 from elixir.fields      import Field
@@ -216 +216 @@
         
         self.property = None # sqlalchemy property
-        
+        self.backref = None  # sqlalchemy backref
+
         #TODO: unused for now
         self.args = args
@@ -240 +241 @@
         properties to the involved entities.
         '''
+        kwargs = {}
+        if self.inverse:
+            # check if the inverse was already processed (and this has already defined
+            # a backref)
+            if self.inverse.backref:
+                kwargs['backref'] = self.inverse.backref
+            else:
+                kwargs = self.get_prop_kwargs()
+
+                # SQLAlchemy doesn't like when 'secondary' is both defined on
+                # the relation and the backref
+                kwargs.pop('secondary', None)
+
+                # define backref for use by the inverse
+                self.backref = backref(self.name, **kwargs)
+                return
+
+        kwargs.update(self.get_prop_kwargs())
+        self.property = relation(self.target, **kwargs)
+        self.entity.mapper.add_property(self.name, self.property)
     
     def setup(self):
@@ -249 +270 @@
             return False
 
-        if self.property:
+        if self.property or self.backref:
             return True
 
@@ -362 +383 @@
         if source_desc.autoload:
             #TODO: test if this works when colname is a list
+
             if self.colname:
                 self.primaryjoin_clauses = \
@@ -429 +451 @@
                                             name=fk_name,
                                             **self.constraint_kwargs))
-    
-    def create_properties(self):
-        kwargs = self.kwargs
+
+    def get_prop_kwargs(self):
+        kwargs = {'uselist': False}
         
         if self.entity.table is self.target.table:
@@ -443 +465 @@
             kwargs['primaryjoin'] = and_(*self.primaryjoin_clauses)
 
-        kwargs['uselist'] = False
-
-        self.property = relation(self.target, **kwargs)
-        self.entity.mapper.add_property(self.name, self.property)
+        kwargs.update(self.kwargs)
+
+        return kwargs
 
 
@@ -470 +491 @@
         self.inverse.setup()
     
-    def create_properties(self):
-        kwargs = self.kwargs
+    def get_prop_kwargs(self):
+        kwargs = {'uselist': self.uselist}
         
         #TODO: for now, we don't break any test if we remove those 2 lines.
@@ -486 +507 @@
             kwargs['primaryjoin'] = and_(*self.inverse.primaryjoin_clauses)
 
-        kwargs['uselist'] = self.uselist
-        
-        self.property = relation(self.target, **kwargs)
-        self.entity.mapper.add_property(self.name, self.property)
+        kwargs.update(self.kwargs)
+
+        return kwargs
 
 
 class HasMany(HasOne):
     uselist = True
-
-    def create_properties(self):
-        if 'order_by' in self.kwargs:
-            self.kwargs['order_by'] = \
+    
+    def get_prop_kwargs(self):
+        kwargs = super(HasMany, self).get_prop_kwargs()
+
+        if 'order_by' in kwargs:
+            kwargs['order_by'] = \
                 self.target._descriptor.translate_order_by(
-                    self.kwargs['order_by'])
-
-        super(HasMany, self).create_properties()
+                    kwargs['order_by'])
+
+        return kwargs
 
 
@@ -653 +675 @@
                                     self.entity.table)
 
-    def create_properties(self):
-        kwargs = self.kwargs
+    def get_prop_kwargs(self):
+        kwargs = {'secondary': self.secondary_table, 
+                  'uselist': self.uselist}
 
         if self.target is self.entity:
@@ -660 +683 @@
             kwargs['secondaryjoin'] = and_(*self.secondaryjoin_clauses)
 
+        kwargs.update(self.kwargs)
+
         if 'order_by' in kwargs:
             kwargs['order_by'] = \
                 self.target._descriptor.translate_order_by(kwargs['order_by'])
 
-        self.property = relation(self.target, secondary=self.secondary_table,
-                                 uselist=self.uselist, **kwargs)
-        self.entity.mapper.add_property(self.name, self.property)
+        return kwargs
 
     def is_inverse(self, other):
@@ -686 +709 @@
     else:
         cols2 = None
+
+    # Build a map of fk constraints pointing to the correct table.
+    # The map is indexed on the local col names.
     constraint_map = {}
     for constraint in local_table.constraints:
         if isinstance(constraint, ForeignKeyConstraint):
-            use_constraint = False
+
+            use_constraint = True
             fk_colnames = []
+
+            # if all columns point to the correct table, we use the constraint
             for fk in constraint.elements:
-                fk_colnames.append(fk.parent.name)
                 if fk.references(target_table):
-                    use_constraint = True
+                    fk_colnames.append(fk.parent.name)
+                else:
+                    use_constraint = False
             if use_constraint:
                 fk_colnames.sort()
@@ -704 +734 @@
     # know the other join is either not used (is None) or has an explicit 
     # match.
+        
+#TODO: rewrite this. Even with the comment, I don't even understand it myself.
     for cols, constraint in constraint_map.iteritems():
         if cols == cols1 or (cols != cols2 and 

elixir/trunk/tests/test_movies.py

@@ -65 +65 @@
         objectstore.clear()
     
+    def test_backref(self):
+        swars = Movie(title="Star Wars", year=1977)
+        glucas = Director(name="George Lucas")
+        swars.director = glucas
+
+        # does it work before a flush?
+        assert swars in glucas.movies
+
     def test_bidirectional(self):
         brunner = Movie(title="Blade Runner", year=1982)