If you include the MULTISCHEMA IS ON clause in your CREATE
    DATABASE statement, you can store your metadata in multiple
    schemas. A database with multiple schemas must organize them
    within catalogs. A catalog is a group of schemas within one
    database.

    You name catalogs in CREATE CATALOG or CREATE DATABASE
    statements. You can also use catalog names to qualify the names
    of other database elements such as schemas, tables, and views.

                                   NOTE

       In syntax diagrams, the column-name syntax element refers to
       either the qualified or unqualified form of the name given
       to the catalog in the CREATE statement. That is, in syntax
       diagrams, the catalog-name is always defined as:

  (B)0catalog-name =                               
                                               
  qwqqqqqq> <name-of-catalog> qqqqqqqqqqqqqqwq>
   x                                        x  
   mq> " q> <alias>.<name-of-catalog> q>"  qj  
                                               

    In each multischema database, SQL creates a catalog named
    RDB$CATALOG. SQL stores all schemas in RDB$CATALOG by default. A
    multischema database must contain at least one catalog, although
    you can create more than one catalog for each database. To
    store a schema in a catalog other than RDB$CATALOG, qualify the
    schema name with the other catalog's name in the CREATE SCHEMA
    statement, or use the SET CATALOG statement to change the default
    catalog before issuing a CREATE SCHEMA statement.