SYSFOREIGNKEYS system table

The SYSFOREIGNKEYS table describes the information specific to foreign key constraints in the current database.

Derby generates a backing index for each foreign key constraint. The name of this index is the same as SYSFOREIGNKEYS.CONGLOMERATEID.

The following table shows the contents of the SYSFOREIGNKEYS system table.

Table 1. SYSFOREIGNKEYS system table
Column Name Type Length Nullable Contents
CONSTRAINTID CHAR 36 false Unique identifier for the foreign key constraint (join with SYSCONSTRAINTS.CONSTRAINTID)
CONGLOMERATEID CHAR 36 false Unique identifier for index backing up the foreign key constraint (join with SYSCONGLOMERATES. CONGLOMERATEID)
KEYCONSTRAINTID CHAR 36 false Unique identifier for the primary key or unique constraint referenced by this foreign key (SYSKEYS.CONSTRAINTID or SYSCONSTRAINTS.CONSTRAINTID)
DELETERULE CHAR 1 false 'R' for NO ACTION (default), 'S' for RESTRICT, 'C' for CASCADE, 'U' for SET NULL
UPDATERULE CHAR 1 false 'R' for NO ACTION (default), 'S' for RESTRICT