- a fair amount of cleanup to the schema package, removal of ambiguous

methods, methods that are no longer needed.  slightly more constrained
useage, greater emphasis on explicitness.
- table_iterator signature fixup, includes fix for [ticket:288]
- the "primary_key" attribute of Table and other selectables becomes
a setlike ColumnCollection object; is no longer ordered or numerically
indexed.  a comparison clause between two pks that are derived from the
same underlying tables (i.e. such as two Alias objects) can be generated
via table1.primary_key==table2.primary_key
- append_item() methods removed from Table and Column; preferably
construct Table/Column/related objects inline, but if needed use
append_column(), append_foreign_key(), append_constraint(), etc.
- table.create() no longer returns the Table object, instead has no
return value.  the usual case is that tables are created via metadata,
which is preferable since it will handle table dependencies.
- added UniqueConstraint (goes at Table level), CheckConstraint
(goes at Table or Column level) fixes [ticket:217]
- index=False/unique=True on Column now creates a UniqueConstraint,
index=True/unique=False creates a plain Index,
index=True/unique=True on Column creates a unique Index.  'index'
and 'unique' keyword arguments to column are now boolean only; for
explcit names and groupings of indexes or unique constraints, use the
UniqueConstraint/Index constructs explicitly.
- relationship of Metadata/Table/SchemaGenerator/Dropper has been
improved so that the schemavisitor receives the metadata object
for greater control over groupings of creates/drops.
- added "use_alter" argument to ForeignKey, ForeignKeyConstraint,
but it doesnt do anything yet.  will utilize new generator/dropper
behavior to implement.

1 files changed, 18 insertions, 17 deletions

diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index c113edaa3..6f51ccbe9 100644
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -658,6 +658,17 @@ class ColumnElement(Selectable, CompareMixin):
         else:
             return self
 
+class ColumnCollection(util.OrderedProperties):
+    def add(self, column):
+        self[column.key] = column
+    def __eq__(self, other):
+        l = []
+        for c in other:
+            for local in self:
+                if c.shares_lineage(local):
+                    l.append(c==local)
+        return and_(*l)
+             
 class FromClause(Selectable):
     """represents an element that can be used within the FROM clause of a SELECT statement."""
     def __init__(self, name=None):
@@ -671,7 +682,7 @@ class FromClause(Selectable):
         visitor.visit_fromclause(self)
     def count(self, whereclause=None, **params):
         if len(self.primary_key):
-            col = self.primary_key[0]
+            col = list(self.primary_key)[0]
         else:
             col = list(self.columns)[0]
         return select([func.count(col).label('tbl_row_count')], whereclause, from_obj=[self], **params)
@@ -735,8 +746,8 @@ class FromClause(Selectable):
         if hasattr(self, '_columns'):
             # TODO: put a mutex here ?  this is a key place for threading probs
             return
-        self._columns = util.OrderedProperties()
-        self._primary_key = []
+        self._columns = ColumnCollection()
+        self._primary_key = ColumnCollection()
         self._foreign_keys = util.Set()
         self._orig_cols = {}
         export = self._exportable_columns()
@@ -1082,7 +1093,7 @@ class Join(FromClause):
     def _proxy_column(self, column):
         self._columns[column._label] = column
         if column.primary_key:
-            self._primary_key.append(column)
+            self._primary_key.add(column)
         for f in column.foreign_keys:
             self._foreign_keys.add(f)
         return column
@@ -1257,9 +1268,9 @@ class TableClause(FromClause):
     def __init__(self, name, *columns):
         super(TableClause, self).__init__(name)
         self.name = self.fullname = name
-        self._columns = util.OrderedProperties()
+        self._columns = ColumnCollection()
         self._foreign_keys = util.Set()
-        self._primary_key = []
+        self._primary_key = util.Set()
         for c in columns:
             self.append_column(c)
         self._oid_column = ColumnClause('oid', self, hidden=True)
@@ -1282,16 +1293,6 @@ class TableClause(FromClause):
             return self._orig_cols
     original_columns = property(_orig_columns)
 
-    def _clear(self):
-        """clears all attributes on this TableClause so that new items can be added again"""
-        self.columns.clear()
-        self.foreign_keys[:] = []
-        self.primary_key[:] = []
-        try:
-            delattr(self, '_orig_cols')
-        except AttributeError:
-            pass
-
     def accept_visitor(self, visitor):
         visitor.visit_table(self)
     def _exportable_columns(self):
@@ -1305,7 +1306,7 @@ class TableClause(FromClause):
             data[self] = self
     def count(self, whereclause=None, **params):
         if len(self.primary_key):
-            col = self.primary_key[0]
+            col = list(self.primary_key)[0]
         else:
             col = list(self.columns)[0]
         return select([func.count(col).label('tbl_row_count')], whereclause, from_obj=[self], **params)