SYSTABLES

Systables is a system catalog table used by several relational database management systems to store metadata about every table in a database, including user tables and views. It forms part of the database’s data dictionary and is maintained by the DBMS.

The information in systables typically includes an internal identifier for each table, the human-readable name, the owner or schema, the type (for example base table or view), and metadata such as creation time, row estimates, and the number of columns. The exact schema varies by implementation, but the table serves as a centralized source of table-level metadata used by the query optimizer, tools, and administrators.

Access to systables is usually restricted to privileged users, with read access granted to developers and tooling. Direct updates to system catalogs are discouraged or unsupported; metadata changes should be performed via approved DDL statements and management utilities.

Users commonly query systables to obtain lists of tables, check dependencies, or look up metadata for schema introspection. Example (informal): select tabname, tabtype from systables where tabtype in ('T','V'); The precise values and column names differ by system. For more portable metadata, many DBMS provide information_schema views or equivalent catalog interfaces.

Systables appears prominently in Informix-style catalogs but the concept exists in other systems under different names, such as sys.tables in SQL Server or pg_catalog.pg_tables in PostgreSQL.