A concept hierarchy is composed of relation schemes with the same concept, in which specialization and generalization can be specified to enrich the semantics of the relational view. Based on the concept hierarchies, a procedure is designed to decompose a global query to local subqueries and a ...
Which aspect(s) of the following can be attacked while rebuttals? A. Generalization. B. Relevance. C. Logic leap. D. Contradiction. E. Assumption. F. All above. 查看完整题目与答案 营销数据库是关于()的综合数据源,并不是一个单纯的客户名单。 A. 企业经营 B. 客户营销 C. 市场状况 ...