This paper examines the expressive power of OCL in terms of navigability and computability. First the expressive power of
OCL is compared with the relational calculus; it is showed that OCL is not equivalent to the relational calculus. Then an
algorithm computing the transitive closure of a binary relation -operation that cannot be encoded in the relational calculus-
is expressed in OCL. Finally the equivalence of OCL with a Turing machine is pondered.
This work was partially supported by the Bayerische Forschungsstiftung.