- merged the "execcontext" branch, refactors engine/dialect codepaths

- much more functionality moved into ExecutionContext, which impacted
the API used by dialects to some degree
- ResultProxy and subclasses now designed sanely
- merged patch for #522, Unicode subclasses String directly,
MSNVarchar implements for MS-SQL, removed MSUnicode.
- String moves its "VARCHAR"/"TEXT" switchy thing into
"get_search_list()" function, which VARCHAR and CHAR can override
to not return TEXT in any case (didnt do the latter yet)
- implements server side cursors for postgres, unit tests, #514
- includes overhaul of dbapi import strategy #480, all dbapi
importing happens in dialect method "dbapi()", is only called
inside of create_engine() for default and threadlocal strategies.
Dialect subclasses have a datamember "dbapi" referencing the loaded
module which may be None.
- added "mock" engine strategy, doesnt require DBAPI module and
gives you a "Connecition" which just sends all executes to a callable.
can be used to create string output of create_all()/drop_all().

1 files changed, 21 insertions, 27 deletions

diff --git a/lib/sqlalchemy/ansisql.py b/lib/sqlalchemy/ansisql.py
index a75263d91..03053b998 100644
--- a/lib/sqlalchemy/ansisql.py
+++ b/lib/sqlalchemy/ansisql.py
@@ -49,14 +49,11 @@ class ANSIDialect(default.DefaultDialect):
     def create_connect_args(self):
         return ([],{})
 
-    def dbapi(self):
-        return None
+    def schemagenerator(self, *args, **kwargs):
+        return ANSISchemaGenerator(self, *args, **kwargs)
 
-    def schemagenerator(self, *args, **params):
-        return ANSISchemaGenerator(*args, **params)
-
-    def schemadropper(self, *args, **params):
-        return ANSISchemaDropper(*args, **params)
+    def schemadropper(self, *args, **kwargs):
+        return ANSISchemaDropper(self, *args, **kwargs)
 
     def compiler(self, statement, parameters, **kwargs):
         return ANSICompiler(self, statement, parameters, **kwargs)
@@ -97,6 +94,9 @@ class ANSICompiler(sql.Compiled):
         
         sql.Compiled.__init__(self, dialect, statement, parameters, **kwargs)
 
+        # if we are insert/update.  set to true when we visit an INSERT or UPDATE
+        self.isinsert = self.isupdate = False
+        
         # a dictionary of bind parameter keys to _BindParamClause instances.
         self.binds = {}
         
@@ -789,13 +789,12 @@ class ANSISchemaBase(engine.SchemaIterator):
         return alterables
 
 class ANSISchemaGenerator(ANSISchemaBase):
-    def __init__(self, engine, proxy, connection, checkfirst=False, tables=None, **kwargs):
-        super(ANSISchemaGenerator, self).__init__(engine, proxy, **kwargs)
+    def __init__(self, dialect, connection, checkfirst=False, tables=None, **kwargs):
+        super(ANSISchemaGenerator, self).__init__(connection, **kwargs)
         self.checkfirst = checkfirst
         self.tables = tables and util.Set(tables) or None
-        self.connection = connection
-        self.preparer = self.engine.dialect.preparer()
-        self.dialect = self.engine.dialect
+        self.preparer = dialect.preparer()
+        self.dialect = dialect
 
     def get_column_specification(self, column, first_pk=False):
         raise NotImplementedError()
@@ -804,7 +803,7 @@ class ANSISchemaGenerator(ANSISchemaBase):
         collection = [t for t in metadata.table_iterator(reverse=False, tables=self.tables) if (not self.checkfirst or not self.dialect.has_table(self.connection, t.name, schema=t.schema))]
         for table in collection:
             table.accept_visitor(self)
-        if self.supports_alter():
+        if self.dialect.supports_alter():
             for alterable in self.find_alterables(collection):
                 self.add_foreignkey(alterable)
 
@@ -857,7 +856,7 @@ class ANSISchemaGenerator(ANSISchemaBase):
 
     def _compile(self, tocompile, parameters):
         """compile the given string/parameters using this SchemaGenerator's dialect."""
-        compiler = self.engine.dialect.compiler(tocompile, parameters)
+        compiler = self.dialect.compiler(tocompile, parameters)
         compiler.compile()
         return compiler
 
@@ -880,11 +879,8 @@ class ANSISchemaGenerator(ANSISchemaBase):
         self.append("PRIMARY KEY ")
         self.append("(%s)" % (string.join([self.preparer.format_column(c) for c in constraint],', ')))
 
-    def supports_alter(self):
-        return True
-
     def visit_foreign_key_constraint(self, constraint):
-        if constraint.use_alter and self.supports_alter():
+        if constraint.use_alter and self.dialect.supports_alter():
             return
         self.append(", \n\t ")
         self.define_foreign_key(constraint)
@@ -927,25 +923,21 @@ class ANSISchemaGenerator(ANSISchemaBase):
         self.execute()
 
 class ANSISchemaDropper(ANSISchemaBase):
-    def __init__(self, engine, proxy, connection, checkfirst=False, tables=None, **kwargs):
-        super(ANSISchemaDropper, self).__init__(engine, proxy, **kwargs)
+    def __init__(self, dialect, connection, checkfirst=False, tables=None, **kwargs):
+        super(ANSISchemaDropper, self).__init__(connection, **kwargs)
         self.checkfirst = checkfirst
         self.tables = tables
-        self.connection = connection
-        self.preparer = self.engine.dialect.preparer()
-        self.dialect = self.engine.dialect
+        self.preparer = dialect.preparer()
+        self.dialect = dialect
 
     def visit_metadata(self, metadata):
         collection = [t for t in metadata.table_iterator(reverse=True, tables=self.tables) if (not self.checkfirst or  self.dialect.has_table(self.connection, t.name, schema=t.schema))]
-        if self.supports_alter():
+        if self.dialect.supports_alter():
             for alterable in self.find_alterables(collection):
                 self.drop_foreignkey(alterable)
         for table in collection:
             table.accept_visitor(self)
 
-    def supports_alter(self):
-        return True
-
     def visit_index(self, index):
         self.append("\nDROP INDEX " + index.name)
         self.execute()
@@ -1099,3 +1091,5 @@ class ANSIIdentifierPreparer(object):
         """Prepare a quoted column name with table name."""
         
         return self.format_column(column, use_table=True, name=column_name)
+
+dialect = ANSIDialect