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Portable Network Graphic  |  1994-05-06  |  117KB  |  816x1056  |  16-bit (665 colors)
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OCR: A relational database consists of tables, each of which is assigned unique name row in table represents relationship among set of values Since table tecbion of such relationships, there close correspondence between the concept of table and the mathematical con cept of relation we define domain to be the set of permitted values for entries in column of table then relation is mathematically fined to be subset Cartesian product list domains Thus we can use the mathematical terms relation and tuple interchangeably with the terms table and row Formal query languages A query language language in which a user requests information from the data base can be either procedural or non procedural-In procedu ral language the user provides seauence of operations that generate fh answer to the query. nonp ...