In this paper, we have studied the problem of completeness of relational query languages. We have etablished a criterion for completeness. A query language was proved to be complete. Since this language is the one used as a standard for completeness this results gives strong theoretical basis to Codd's definition of completeness. There are however some limitations to this notion of completeness: for instance there is no first order formula describing the transitive closure r* of a binary relation r ! While this seems at first to be in contradiction with theorem 2, one should recall that the notion of completeness we have introduced is static. Therefore, for any configuration τ consisting of a binary relation r there exists a formula rτ of the first order calculus describing the transitive closure of r, but this formula depends on τ and there is no formula describing the mapping which associates with a binary relation its transitive closure.
CITATION STYLE
Bancilhon, F. (1978). On the completeness of query languages for relational data bases. In Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (Vol. 64 LNCS, pp. 112–123). Springer Verlag. https://doi.org/10.1007/3-540-08921-7_60
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