From 3b68c258fd527c15633162ef7312e52fbc71db47 Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Sat, 16 Jul 2005 01:44:52 +0000
Subject: [PATCH]

---
 lib/sqlalchemy/mapper.py | 58 ++++++++++++++++++++++++++++++++++------
 1 file changed, 50 insertions(+), 8 deletions(-)

diff --git a/lib/sqlalchemy/mapper.py b/lib/sqlalchemy/mapper.py
index 252bac984d..dfd8bafa3e 100644
--- a/lib/sqlalchemy/mapper.py
+++ b/lib/sqlalchemy/mapper.py
@@ -31,7 +31,6 @@ usermapper = Mapper(
 
 addressmapper = Mapper(Address, addresses, properties = {
     'street': addresses.address_1,
-    '*' : addresses
 })
 """
 
@@ -39,28 +38,71 @@ import sqlalchemy.sql as sql
 import sqlalchemy.schema as schema
 
 class Mapper:
-    def __init__(self, class_, table, properties):
+    def __init__(self, class_, table, properties, identitymap = None):
         self.class_ = class_
         self.table = table
         self.properties = properties
+        if identitymap is not None:
+            self.identitymap = identitymap
+        else:
+            self.identitymap = _global_identitymap
 
     def instance(self, row):
         pass
-                
-    def select_whereclause(self, whereclause, **params):
+
+    def get(self, id):
+        """returns an instance of the object based on the given ID."""
         pass
+        
+    def _select_whereclause(self, whereclause, **params):
+        # make select statement
+
+        
+        return self._select_statement(statement, **params)
+
     
-    def select_statement(self, statement, **params):
+    def _select_statement(self, statement, **params):
         pass
 
     def select(self, arg, **params):
+        """selects instances of the object from the database.  
+        
+        arg can be any ClauseElement, which will form the criterion with which to
+        load the objects.
+        
+        For more advanced usage, arg can also be a Select statement object, which
+        will be executed and its resulting rowset used to build new object instances.  
+        in this case, the developer must insure that an adequate set of columns exists in the 
+        rowset with which to build new object instances."""
         if isinstance(arg, sql.Select):
-            return self.select_statement(arg, **params)
+            return self._select_statement(arg, **params)
         else:
-            return self.select_whereclause(arg, **params)
+            return self._select_whereclause(arg, **params)
         
     def save(self, object):
         pass
         
     def delete(self, whereclause = None, **params):
-        pass
\ No newline at end of file
+        pass
+        
+        
+class IdentityMap:
+    def __init__(self):
+        self.map = {}
+        
+    def get(self, row, class_, table):
+        """given a database row, a class to be instantiated, and a table corresponding 
+        to the row, returns a corrseponding object instance, if any, from the identity
+        map.  the primary keys specified in the table will be used to indicate which
+        columns from the row form the effective key of the instance."""
+        pass
+        
+    def put(self, instance, table):
+        """puts this object instance, corresponding to a row from the given table, into 
+        the identity map.  the primary keys specified in the table will be used to 
+        indicate which properties of the instance form the effective key of the instance."""
+        
+        pass
+    
+    
+_global_identitymap = IdentityMap()
-- 
2.47.2