A relational model of data for large shared data banks
Communications of the ACM
Unacceptable file operations in a relational data base
SIGFIDET '71 Proceedings of the 1971 ACM SIGFIDET (now SIGMOD) Workshop on Data Description, Access and Control
A data base sublanguage founded on the relational calculus
SIGFIDET '71 Proceedings of the 1971 ACM SIGFIDET (now SIGMOD) Workshop on Data Description, Access and Control
Storage structure and physical data independence
SIGFIDET '71 Proceedings of the 1971 ACM SIGFIDET (now SIGMOD) Workshop on Data Description, Access and Control
Unacceptable file operations in a relational data base
SIGFIDET '71 Proceedings of the 1971 ACM SIGFIDET (now SIGMOD) Workshop on Data Description, Access and Control
A data base sublanguage founded on the relational calculus
SIGFIDET '71 Proceedings of the 1971 ACM SIGFIDET (now SIGMOD) Workshop on Data Description, Access and Control
Storage structure and physical data independence
SIGFIDET '71 Proceedings of the 1971 ACM SIGFIDET (now SIGMOD) Workshop on Data Description, Access and Control
Bibliography on data base structures
ACM SIGMIS Database
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This paper presents an architecture for a data base system which is capable of providing data independence at two levels, viz physical and logical. The architecture employs a schema, which gives an abstract picture of the physical data base, and a subschema, which contains the definitions of an application program's logical files. The language for writing these logical file definitions is then discussed, and a number of features which should be provided in such a language are identified, and descrioed. In particular it is shown that the language should include the quantifiers of the predicate calculus, and should be capable of defining files which span several files in the schema. The use of the subschema in providing logical data independence is then demonstrated, and an appropriate application program discipline discussed. This is the first of two associated papers, the second of which deals with the complementary problems of storage structure and physical data independence.