In the database field, the requirement of high level facilities for retrieval/update operations is now increasing rapidly. Our approach from the relational database point of view for contribution to this problem is to provide 1) efficient processing of relational retrieval/ update operations, and 2) a high level user interface. In order to achieve this goal, a new concept concerning "abstracted characteristics" is presented. Abstracted characteristics are defined to be characteristics abstracted from sets of tuples in relations stored in the database. A classification of abstracted characteristics is presented. Functional dependencies, which play an important role in relational database design, and time-dependent functional dependencies are pointed out to be useful in processing retrieval/update operations. Some important applications of abstracted characteristics are discussed. Among them: 1) efficient processing of retrieval/update operations, 2) powerful view update checking facilities, 3) providing some rough meanings of null responses and 4) a high level user interface.
['C. Le Viet', 'Yahiko Kambayashi', 'K. Tanaka', 'Shuzo Yajima']
Use of abstracted characteristics of data in relational databases