From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Mon, 27 Mar 2006 02:58:20 +0000 (+0000)
Subject: tweak to mapper to allow inheritance on the same table.
X-Git-Tag: rel_0_1_5~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=19e9af44c0fcf2ac36c8957c0d23b691e111e359;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

tweak to mapper to allow inheritance on the same table.
---

diff --git a/CHANGES b/CHANGES
index a996bd5647..e454a4e65a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -31,6 +31,8 @@ commit
 concept of relations on a mapper being made towards the "local" table for that
 mapper, not the tables it inherits.  allows more complex compositional patterns
 to work with lazy/eager loading.
+- added support for mappers to inherit from others based on the same table, 
+just specify the same table as that of both parent/child mapper.
 - some minor speed improvements to the attributes system with regards to 
 instantiating and populating new objects. 
 - fixed MySQL binary unit test
diff --git a/lib/sqlalchemy/mapping/mapper.py b/lib/sqlalchemy/mapping/mapper.py
index ed07983e44..a0de86df4f 100644
--- a/lib/sqlalchemy/mapping/mapper.py
+++ b/lib/sqlalchemy/mapping/mapper.py
@@ -71,22 +71,24 @@ class Mapper(object):
         if inherits is not None:
             self.primarytable = inherits.primarytable
             # inherit_condition is optional.
-            if inherit_condition is None:
-                # figure out inherit condition from our table to the immediate table
-                # of the inherited mapper, not its full table which could pull in other 
-                # stuff we dont want (allows test/inheritance.InheritTest4 to pass)
-                inherit_condition = sql.join(inherits.noninherited_table, table).onclause
-            self.table = sql.join(inherits.table, table, inherit_condition)
-            #print "inherit condition", str(self.table.onclause)
-
-            # generate sync rules.  similarly to creating the on clause, specify a 
-            # stricter set of tables to create "sync rules" by,based on the immediate
-            # inherited table, rather than all inherited tables
-            self._synchronizer = sync.ClauseSynchronizer(self, self, sync.ONETOMANY)
-            self._synchronizer.compile(self.table.onclause, util.HashSet([inherits.noninherited_table]), TableFinder(table))
-            # the old rule
-            #self._synchronizer.compile(self.table.onclause, inherits.tables, TableFinder(table))
+            if not table is inherits.noninherited_table:
+                if inherit_condition is None:
+                    # figure out inherit condition from our table to the immediate table
+                    # of the inherited mapper, not its full table which could pull in other 
+                    # stuff we dont want (allows test/inheritance.InheritTest4 to pass)
+                    inherit_condition = sql.join(inherits.noninherited_table, table).onclause
+                self.table = sql.join(inherits.table, table, inherit_condition)
+                #print "inherit condition", str(self.table.onclause)
 
+                # generate sync rules.  similarly to creating the on clause, specify a 
+                # stricter set of tables to create "sync rules" by,based on the immediate
+                # inherited table, rather than all inherited tables
+                self._synchronizer = sync.ClauseSynchronizer(self, self, sync.ONETOMANY)
+                self._synchronizer.compile(self.table.onclause, util.HashSet([inherits.noninherited_table]), TableFinder(table))
+                # the old rule
+                #self._synchronizer.compile(self.table.onclause, inherits.tables, TableFinder(table))
+            else:
+                self._synchronizer = None
             self.inherits = inherits
             self.noninherited_table = table
         else: