The Chase is a simple fixpoint algorithm, proposed 30 years ago, for testing and enforcing implication of data dependencies in database systems. It plays important roles in database theory as well as in practical applications such as data exchange, data integration, data warehousing, federated databases and others. It is also used, directly or indirectly, on an everyday basis by people who desi...

ICROPHTHALMIA has been reported in a number of rat colonies M (JONES 1925; KING 1931; HAIN 1936; BROWMAN 1941, 1943; QUISSENBERRY and BROWN 1942 ; CAMPBELL 1944). Published reports indicate that not only the embryological development but also the final eye condition may be quite varied in the several colonies (see BROWMAN and RAMSEY 1943 and CAMPBELL 1944). The mode of inheritance of this chara...

The initial and basic role of the chase procedure was to test logical implication between sets ofdependencies in order to determine equivalence of database instances known to satisfy a givenset of dependencies and to determine query equivalence under database constrains. Recently thechase procedure has experienced a revival due to its application in data exchange. In this chapter<lb...