SQL Catalog

The SQL Catalog (aka database catalog or data dictionary) consists of a set of system tables and views that contain metadata about the objects defined in the database. These system tables and views are stored in the system schemas: sys and tmp. You can query these tables and views with SQL, examples:

SELECT * FROM sys.schemas WHERE NOT system;
SELECT * FROM sys.tables  WHERE name LIKE 'c%';
SELECT * FROM sys.table_types;

SELECT tt.table_type_name, t.*
  FROM sys.tables t
  JOIN sys.table_types tt ON t.type = tt.table_type_id
 WHERE name LIKE 'c%';

SELECT * FROM sys.columns
 WHERE table_id IN (SELECT id FROM sys.tables WHERE name = 'tables' AND schema_id = 2000);

SELECT * FROM sys.function_types;
SELECT * FROM sys.functions WHERE name = 'max';

SELECT f.id, s.name as schema_nm, f.name
     , (select listagg(a.name ||' '||a.type, ', ') from sys.args a where a.inout = 1 and a.func_id = f.id) as arg_in_list
     , (select listagg(a.type, ', ') from sys.args a where a.inout = 0 and a.func_id = f.id) as returns_list
     , f.mod, f.language, f.type, f.func
  FROM sys.functions f
  JOIN sys.schemas s ON s.id = f.schema_id
 ORDER BY s.name, f.name

Besides the Catalog system tables and views MonetDB also supports ISO standard information_schema views: