SQL Guide : Using SQL for database administration : Managing database objects : Creating a catalog
  
Creating a catalog
CREATE CATALOG catalog_name
Only the creator of the database or users having SYS_ADMIN_ROLE have privileges to create or drop catalogs.
The following example creates a catalog named C and assumes the userid is SMITH
CREATE CATALOG C;
SET CATALOG C;
CREATE TABLE T (i INTEGER);
SELECT * FROM T;
--The name T is resolved to C.SMITH.T
See also
Managing database objects