The syschecks system catalog table describes each check constraint defined in the database. Because the syschecks table stores both the ASCII text and a binary encoded form of the check constraint, it contains multiple rows for each check constraint. The syschecks table has the following columns.
Table 1. SYSCHECKS table column descriptions
Column Type Explanation
constrid INTEGER Unique code identifying the constraint
type CHAR(1) Form in which the check constraint is stored: B = Binary encoded s = Select T = Text
seqno SMALLINT Line number of the check constraint
checktext CHAR(32) Text of the check constraint
The text in the checktext column associated with B type in the type column is in computer-readable format. To view the text associated with a particular check constraint, use the following query with the appropriate constrid code:
SELECT * FROM syschecks WHERE constrid=10 AND type='T'

Each check constraint described in the syschecks table also has its own row in the sysconstraints table.

A composite index on the constrid, type, and seqno columns allows only unique values.