To provide a high degree of data independence.
To provide a community view of the data of spartan(严格的) simplicity, so that a wide variety of users in an enterrprise, ranging from the most computer-naive to the most computer-sophiscated, can interact with a common model(while not prohibiting superimposed user views for specialized purposes).
To simplify the potentially formidable(困难的) job of the DBA.
To introduce a theoretical foundation (albeit(虽然) modest) into database management(a field sadly lacking in solid principle and guidelines).
To merge the fact-retrieval and file-management fields in preparation for the addition at a later time of inferential(推论的) services in the commercial world.
To lift database application programming to a new level - a level in which sets (and more specifically relations) are treated as operands instead of being processed element by element.

内容摘自C. J. Date的书Database In Depth, 其引用的是E. F. Codd 1974年的文章－－Recent Investigation into Relational Data Base Systems中的内容。

ITPub博客

Objectives of the Relational Model