make migrate.changeset.databases PEP-8 clean and add it to the API docs

1 files changed, 61 insertions, 31 deletions

diff --git a/migrate/changeset/databases/oracle.py b/migrate/changeset/databases/oracle.py
index 1bb616d..35b146c 100644
--- a/migrate/changeset/databases/oracle.py
+++ b/migrate/changeset/databases/oracle.py
@@ -1,54 +1,74 @@
-from migrate.changeset import ansisql,exceptions
+"""
+   Oracle database specific implementations of changeset classes.
+"""
+
+from migrate.changeset import ansisql, exceptions
 from sqlalchemy.databases import oracle as sa_base
 import sqlalchemy as sa
 
 OracleSchemaGenerator = sa_base.OracleSchemaGenerator
 
-class OracleColumnGenerator(OracleSchemaGenerator,ansisql.ANSIColumnGenerator):
+
+class OracleColumnGenerator(OracleSchemaGenerator,
+                            ansisql.ANSIColumnGenerator):
     pass
+
+
 class OracleColumnDropper(ansisql.ANSIColumnDropper):
     pass
-class OracleSchemaChanger(OracleSchemaGenerator,ansisql.ANSISchemaChanger):
-    def get_column_specification(self,column,**kwargs):
-        # Ignore the NOT NULL generated 
-        override_nullable = kwargs.pop('override_nullable',None)
+
+
+class OracleSchemaChanger(OracleSchemaGenerator, ansisql.ANSISchemaChanger):
+
+    def get_column_specification(self, column, **kwargs):
+        # Ignore the NOT NULL generated
+        override_nullable = kwargs.pop('override_nullable', None)
         if override_nullable:
             orig = column.nullable
             column.nullable = True
-        ret=super(OracleSchemaChanger,self).get_column_specification(column,**kwargs)
+        ret = super(OracleSchemaChanger, self).get_column_specification(
+            column, **kwargs)
         if override_nullable:
             column.nullable = orig
         return ret
-            
-    def visit_column(self,delta):
+
+    def visit_column(self, delta):
         keys = delta.keys()
-        if 'type' in keys or 'nullable' in keys or 'default' in keys or 'server_default' in keys:
-            self._run_subvisit(delta,self._visit_column_change)
+        if 'type' in keys or 'nullable' in keys or 'default' in keys \
+                or 'server_default' in keys:
+            self._run_subvisit(delta, self._visit_column_change)
         if 'name' in keys:
-            self._run_subvisit(delta,self._visit_column_name)
-    def _visit_column_change(self,table_name,col_name,delta):
-        if not hasattr(delta,'result_column'):
-            # Oracle needs the whole column definition, not just a lone name/type
+            self._run_subvisit(delta, self._visit_column_name)
+
+    def _visit_column_change(self, table_name, col_name, delta):
+        if not hasattr(delta, 'result_column'):
+            # Oracle needs the whole column definition, not just a
+            # lone name/type
             raise exceptions.NotSupportedError(
                 "A column object is required to do this")
-                
+
         column = delta.result_column
-        # Oracle cannot drop a default once created, but it can set it to null. 
-        # We'll do that if default=None
-        # http://forums.oracle.com/forums/message.jspa?messageID=1273234#1273234
-        dropdefault_hack = (column.server_default is None and 'server_default' in delta.keys())
-        # Oracle apparently doesn't like it when we say "not null" if the
-        # column's already not null. Fudge it, so we don't need a new function
-        notnull_hack = ((not column.nullable) and ('nullable' not in delta.keys()))
-        # We need to specify NULL if we're removing a NOT NULL constraint
+        # Oracle cannot drop a default once created, but it can set it
+        # to null.  We'll do that if default=None
+        # http://forums.oracle.com/forums/message.jspa?\
+        # messageID=1273234#1273234
+        dropdefault_hack = (column.server_default is None \
+                                and 'server_default' in delta.keys())
+        # Oracle apparently doesn't like it when we say "not null" if
+        # the column's already not null. Fudge it, so we don't need a
+        # new function
+        notnull_hack = ((not column.nullable) \
+                            and ('nullable' not in delta.keys()))
+        # We need to specify NULL if we're removing a NOT NULL
+        # constraint
         null_hack = (column.nullable and ('nullable' in delta.keys()))
-        
-                
-        if dropdefault_hack: 
+
+        if dropdefault_hack:
             column.server_default = sa.PassiveDefault(sa.sql.null())
         if notnull_hack:
             column.nullable = True
-        colspec=self.get_column_specification(column,override_nullable=null_hack)
+        colspec=self.get_column_specification(column,
+                                              override_nullable=null_hack)
         if null_hack:
             colspec += ' NULL'
         if notnull_hack:
@@ -59,18 +79,28 @@ class OracleSchemaChanger(OracleSchemaGenerator,ansisql.ANSISchemaChanger):
         self.start_alter_table(table_name)
         self.append("MODIFY ")
         self.append(colspec)
+
+
 class OracleConstraintCommon(object):
-    def get_constraint_name(self,cons):
+
+    def get_constraint_name(self, cons):
         # Oracle constraints can't guess their name like other DBs
         if not cons.name:
             raise exceptions.NotSupportedError(
                 "Oracle constraint names must be explicitly stated")
         return cons.name
-class OracleConstraintGenerator(OracleConstraintCommon,ansisql.ANSIConstraintGenerator):
+
+
+class OracleConstraintGenerator(OracleConstraintCommon,
+                                ansisql.ANSIConstraintGenerator):
     pass
-class OracleConstraintDropper(OracleConstraintCommon,ansisql.ANSIConstraintDropper):
+
+
+class OracleConstraintDropper(OracleConstraintCommon,
+                              ansisql.ANSIConstraintDropper):
     pass
 
+
 class OracleDialect(ansisql.ANSIDialect):
     columngenerator = OracleColumnGenerator
     columndropper = OracleColumnDropper