- [feature] Added new support for remote "schemas":

    - MetaData() accepts "schema" and "quote_schema"
      arguments, which will be applied to the same-named
      arguments of a Table
      or Sequence which leaves these at their default
      of ``None``.
    - Sequence accepts "quote_schema" argument
    - tometadata() for Table will use the "schema"
      of the incoming MetaData for the new Table
      if the schema argument is explicitly "None"
    - Added CreateSchema and DropSchema DDL
      constructs - these accept just the string
      name of a schema and a "quote" flag.
    - When using default "schema" with MetaData,
      ForeignKey will also assume the "default" schema
      when locating remote table.  This allows the "schema"
      argument on MetaData to be applied to any
      set of Table objects that otherwise don't have
      a "schema".
    - a "has_schema" method has been implemented
      on dialect, but only works on Postgresql so far.
    Courtesy Manlio Perillo, [ticket:1679]

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 7cc4a1e68..3ae60f696 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -952,6 +952,19 @@ class PGDialect(default.DefaultDialect):
     def _get_default_schema_name(self, connection):
         return connection.scalar("select current_schema()")
 
+    def has_schema(self, connection, schema):
+        cursor = connection.execute(
+            sql.text(
+                "select nspname from pg_namespace where lower(nspname)=:schema",
+                bindparams=[
+                    sql.bindparam(
+                        'schema', unicode(schema.lower()),
+                        type_=sqltypes.Unicode)]
+            )
+        )
+
+        return bool(cursor.first())
+
     def has_table(self, connection, table_name, schema=None):
         # seems like case gets folded in pg_class...
         if schema is None: