Tech Report CS-89-19

A Query Algebra for Object-Oriented Databases

Gail M. Shaw and Stanley B. Zdonik

March 1989


We define an algebra that synthesizes relational query concepts with object-oriented databases. The algebra fully supports abstract data types and object identity while providing associative access to objects, including a unique join capability. The operations take an abstract view of objects and access typed collections of objects through the public interface defined for the type. The algebra supports access to relationships implied by the structure of the objects, as well as the definition and creation of new relationships between objects. The structure of the algebra and the abstract access to objects offer opportunities for query optimization.

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