The Tarski algebra provides an algebraic foundation for object-based query languages. Thisis demonstrated by showing how queries expressed in a graph-oriented query language (basedon the functional data model) can be translated into the... more
The Tarski algebra provides an algebraic foundation for object-based query languages. Thisis demonstrated by showing how queries expressed in a graph-oriented query language (basedon the functional data model) can be translated into the Tarski algebra. The graphical representationof queries in combination with the Tarski algebra is a convenient mechanism to studyoptimization in the context of object based query languages. We then propose extensions to theTarski algebra that facilitate...
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We introduce the uniform data model to reason about relational data and meta-data query processing. The principal property of the uniform data model is that both meta-data and data are organized in uniformly shaped information objects.... more
We introduce the uniform data model to reason about relational data and meta-data query processing. The principal property of the uniform data model is that both meta-data and data are organized in uniformly shaped information objects. This uniform treatment of ...
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Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the VLDB copyright notice and the tide of the publication and its date appear,... more
Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the VLDB copyright notice and the tide of the publication and its date appear, and notice is given that copying is by ...
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Unnormalized relations permit components of tuples to be relation instances themselves instead of atomic values. Such structures do not always represent the restructuring of a flat (1NF) relation. It is shown that for one-level structures... more
Unnormalized relations permit components of tuples to be relation instances themselves instead of atomic values. Such structures do not always represent the restructuring of a flat (1NF) relation. It is shown that for one-level structures (nesting is permitted only over sets of attributes) there is a polynomial time algorithm to determine whether the structure is the result of restructuring a flat relation with a sequence of NEST operations.
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Object-oriented applications of database systems require database transformations involoving nonstandard functionalities such as set manipulation and object creation, that is, the introduction of new domain elements. To deal with thse... more
Object-oriented applications of database systems require database transformations involoving nonstandard functionalities such as set manipulation and object creation, that is, the introduction of new domain elements. To deal with thse functionalities, Abiteboul and Kanellakis [1989] introduced the “determinate” transformations as a generalization of the standard domain-preserving transformations. The obvious extensions of complete standard database programming languages, however, are not complete for the determinate transformations. To remedy this mismatch, the “constructive” transformations are proposed. It is shown that the constructive transformations are precisely the transformations that can be expressed in said extensions of complete standard languages. Thereto, a close correspondence between object creation and the construction of hereditarily finite sets is established. A restricted version of the main completeness result for the case where only list manipulations are involv...