making sequences, column defaults independently executeable

3 files changed, 20 insertions, 9 deletions

diff --git a/lib/sqlalchemy/databases/postgres.py b/lib/sqlalchemy/databases/postgres.py
index 592bac79c..105fe7a76 100644
--- a/lib/sqlalchemy/databases/postgres.py
+++ b/lib/sqlalchemy/databases/postgres.py
@@ -218,7 +218,7 @@ class PGSQLEngine(ansisql.ANSISQLEngine):
     def schemadropper(self, **params):
         return PGSchemaDropper(self, **params)
 
-    def defaultrunner(self, proxy):
+    def defaultrunner(self, proxy=None):
         return PGDefaultRunner(self, proxy)
         
     def get_default_schema_name(self):
@@ -346,7 +346,7 @@ class PGSchemaDropper(ansisql.ANSISchemaDropper):
             self.execute()
 
 class PGDefaultRunner(ansisql.ANSIDefaultRunner):
-    def get_column_default(self, column):
+    def get_column_default(self, column, isinsert=True):
         if column.primary_key:
             # passive defaults on primary keys have to be overridden
             if isinstance(column.default, schema.PassiveDefault):
diff --git a/lib/sqlalchemy/engine.py b/lib/sqlalchemy/engine.py
index d07dd5734..0f6b65909 100644
--- a/lib/sqlalchemy/engine.py
+++ b/lib/sqlalchemy/engine.py
@@ -265,7 +265,7 @@ class SQLEngine(schema.SchemaEngine):
         """
         raise NotImplementedError()
 
-    def defaultrunner(self, proxy):
+    def defaultrunner(self, proxy=None):
         """Returns a schema.SchemaVisitor instance that can execute the default values on a column.
         The base class for this visitor is the DefaultRunner class inside this module.
         This visitor will typically only receive schema.DefaultGenerator schema objects.  The given 
@@ -275,7 +275,7 @@ class SQLEngine(schema.SchemaEngine):
         
         defaultrunner is called within the context of the execute_compiled() method."""
         return DefaultRunner(self, proxy)
-        
+    
     def compiler(self, statement, parameters):
         """returns a sql.ClauseVisitor which will produce a string representation of the given
         ClauseElement and parameter dictionary.  This object is usually a subclass of 
@@ -529,7 +529,7 @@ class SQLEngine(schema.SchemaEngine):
         self.post_exec(proxy, compiled, parameters, **kwargs)
         return ResultProxy(cursor, self, typemap=compiled.typemap)
 
-    def execute(self, statement, parameters, connection=None, cursor=None, echo=None, typemap=None, commit=False, return_raw=False, **kwargs):
+    def execute(self, statement, parameters=None, connection=None, cursor=None, echo=None, typemap=None, commit=False, return_raw=False, **kwargs):
         """executes the given string-based SQL statement with the given parameters.  
 
         The parameters can be a dictionary or a list, or a list of dictionaries or lists, depending
diff --git a/lib/sqlalchemy/schema.py b/lib/sqlalchemy/schema.py
index a11a1539e..17e421f22 100644
--- a/lib/sqlalchemy/schema.py
+++ b/lib/sqlalchemy/schema.py
@@ -434,11 +434,12 @@ class ForeignKey(SchemaItem):
         self.parent.table.foreign_keys.append(self)
 
 class DefaultGenerator(SchemaItem):
-    """Base class for column "default" values, which can be a plain default
-    or a Sequence."""
+    """Base class for column "default" values."""
     def _set_parent(self, column):
         self.column = column
         self.column.default = self
+    def execute(self):
+        return self.accept_schema_visitor(self.engine.defaultrunner(self.engine.execute))
     def __repr__(self):
         return "DefaultGenerator()"
 
@@ -464,17 +465,27 @@ class ColumnDefault(DefaultGenerator):
         
 class Sequence(DefaultGenerator):
     """represents a sequence, which applies to Oracle and Postgres databases."""
-    def __init__(self, name, start = None, increment = None, optional=False):
+    def __init__(self, name, start = None, increment = None, optional=False, engine=None):
         self.name = name
         self.start = start
         self.increment = increment
         self.optional=optional
+        self.engine = engine
     def __repr__(self):
         return "Sequence(%s)" % string.join(
              [repr(self.name)] +
              ["%s=%s" % (k, repr(getattr(self, k))) for k in ['start', 'increment', 'optional']]
             , ',')
-    
+    def _set_parent(self, column):
+        super(Sequence, self)._set_parent(column)
+        column.sequence = self
+        if self.engine is None:
+            self.engine = column.table.engine
+    def create(self):
+       self.engine.create(self)
+       return self
+    def drop(self):
+       self.engine.drop(self)
     def accept_schema_visitor(self, visitor):
         """calls the visit_seauence method on the given visitor."""
         return visitor.visit_sequence(self)