syskeys

Provides information about keys associated with indexes, including the columns that make up each index key.

Name	Datatype	Description
id	int	The object ID of the table to which the key definition belongs.
type	smallint	The type of a key record. The possible values are: 1 – A primary key. 2 – A foreign key. 3 – A common key.
depid	int null	The object ID of the dependent or referenced table associated with the key.
keycnt	int null	The number of key columns that contain non-null values in the key definition.
size	int null	Reserved for internal system use.
key1 ... key8	smallint null	The column IDs representing the key columns in the table.
depkey1 ... depkey8	smallint null	The column IDs in the dependent or referenced table that correspond to the key columns.
spare1	smallint	Reserved for internal system use.