There is two way for a workaround :
1) add a name to all your constraints
2) retrieve the name of the constraint in meta data tables or views

1) add a name to the constraint :

ALTER TABLE ... ADD CONSTRAINT MyConstraint ...
MyConstraint will be the name of the constraint

2) retrieving the constraint name

SELECT CONSTRAINT_NAME
FROM INFORMATION_SCH EMA.TABLE_CONST RAINTS...