In the context of relational as well as deductive databases, correct and efficient integrity checking is a crucial issue, as, without any guarantee of data consistency, the answers to queries cannot be trusted. To be of any practical use, any method for integrity checking must support aggregates and arithmetic constraints, which are among the most widespread constructs in current database technology. In this paper we propose a method of practical relevance that can be used to simplify integrity constraints possibly containing aggregates and arithmetic expressions. Simplified versions of the integrity constraints are derived at database design time and can be tested before the execution of any update. In this way, virtually no time is spent for optimization or rollbacks at run time. Both set and bag semantics are considered.