SYSREFERENCES

The sysreferences system catalog table lists all referential constraints on columns. It contains a row for each referential constraint in the database.
Table 1. SYSREFERENCES table column descriptions

Column Type Explanation
constrid INTEGER Code uniquely identifying the constraint
primary INTEGER Identifying code of the corresponding primary key
ptabid INTEGER Identifying code of the table that is the primary key
updrule CHAR(1) Reserved for future use; displays an R
delrule CHAR(1) Whether constraint uses cascading delete or restrict rule:
  • C = Cascading delete
  • R = Restrict (default)
matchtype CHAR(1) Reserved for future use; displays an N
pendant CHAR(1) Reserved for future use; displays an N

The constrid column is indexed and allows only unique values. The primary column is indexed and allows duplicate values.