sys.check_constraints

每个用作 CHECK 约束（sys.objects.type = C）的对象都在表中占一行。

SELECT  name
FROM    sys.check_constraints

-- equal to
SELECT  o.name
FROM    sys.sysobjects o
        JOIN sys.sysconstraints s ON o.parent_obj = s.id
WHERE   o.xtype = 'C'
GROUP BY o.name

sys.check_constraints (Transact-SQL)