Each database has a set of system catalog tables that store information (for example, metadata) required by Ingres. The System Catalog Interface (SCI) is a set of views on top of these system catalog tables, and a set of tables that can be queried through SQL statements and therefore used in applications to access (but not update) information about the database.

If you are developing applications that need to query the system catalogs, you must use the Standard Catalog Interface, so that your applications will be upwardly compatible.

All database users can read the Standard Catalog Interface catalogs, but only a privileged user can update them.

To display the underlying view, use the SQL statement HELP VIEW. To display the format of catalogs, use the SQL statement HELP (see Example of HELP VIEW and HELP Statements).

The length of character fields, as listed in the length column, is a maximum length; the actual length of the field may be installation dependent. The values are left-justified and the columns are non-nullable.

Unless otherwise stated, dates are displayed as Ingres dates, that is, 25-byte character strings with the following format:

When developing applications that access SCI, storage should be allocated based on the length shown in the Data Type column in the descriptions below.