We propose a new method for efficiently checking OCL constraints by means of SQL queries. That is, an OCL constraint is satisfied if its corresponding SQL query returns the empty set. Such queries are computed in an incremental way since, whenever a change in the data occurs, only the constraints that may be violated because of such change are checked and only the relevant values given by the change are taken into account. Moreover, the queries we generate do not contain nested subqueries nor procedures. In this way, we take advantage of relational DBMS capabilities and we get an efficient check of OCL constraints.