1970 ARelationalModelofDataforLargeS

(Codd, 1970) ⇒ Edgar F. Codd. (1970). “A Relational Model of Data for Large Shared Data Banks.” In: Communications of the ACM Journal, 13(6). doi:10.1145/362384.362685

Subject Headings: Tuple Relational Calculus.

Notes

Cited By

Quotes

Abstract

Future users of large data banks must be protected from having to know how the data is organized in the machine (the internal representation). A prompting service which supplies such information is not a satisfactory solution. Activities of users at terminals and most application programs should remain unaffected when the internal representation of data is changed and even when some aspects of the external representation are changed. Changes in data representation will often be needed as a result of changes in query, update, and report traffic and natural growth in the types of stored information.

Existing noninferential, formatted data systems provide users with tree-structured files or slightly more general network models of the data. In Section 1, inadequacies of these models are discussed. A model based on n-ary relations, a normal form for data base relations, and the concept of a universal data sublanguage are introduced. In Section 2, certain operations on relations (other than logical inference) are discussed and applied to the problems of redundancy and consistency in the [[user's model.</par>]]

References

;

	Author	volume	Date Value	title	type	journal	titleUrl	doi	note	year
1970 ARelationalModelofDataforLargeS	Edgar F. Codd			A Relational Model of Data for Large Shared Data Banks				10.1145/362384.362685		1970