After having noted the limits of programming interfaces for relational databases, ALCATEL ALSTHOM RECHERCHE have defined a high- level interface (named BLOOD) between the object-oriented language SPOKE1 and Rela- 1 tional Database Management Systems. This in- i terface allows the definition of complex object types, which instances are built with the data extracted from the database. The data from the database are manipulated through these ob- jects via the statements of the object-oriented language. The user's operations on the objects are executed using the corresponding accesses to the database and this is completely transparent to the user. BLOOD therefore allows the user to define a conceptual object-oriented schema of an existing database and allows the manipulation of these data in terms of objects. The system of objects maintains the consistency between the language objects and the relational database. The defini- tion of complex objects allows the maintenance of the referential integrity. Finally, BLOOD in- cludes algebraic operators which allow the exeSATEL