华南理工软件学院2015期末考试-数据库系统A卷.doc

诚信应考,考试作弊将带来严重后果！ 华南理工大学期末考试 《数据库系统》试卷 (A) 注意事项：1. 考前请将密封线内填写清楚； 2. 所有答案请答在答题纸上； 3．考试形式：闭卷； 4. 本试卷共 两 大题，满分100分， 考试时间120分钟。 题 号 一 二 总分 得 分 评卷人 Part I [20 pts.] (1pt each) Fill in the blanks with the best answer. The collection of information stored in the database at a particular moment is called an ________ of the database. The overall design of the data base is called the database ________ . A relation schema is in ________ normal from if for all in + , at least one of the following holds: is ________ ; is a superkey for ; Each attribute in is contained in a candidate key for . Let be a relation schema , and from a decomposition of . Decomposition is a ________ if for all legal database instances of , . In E-R model , on entity is represented by a set of ________ . A ________ is an association among several entities . Assume relation has blocks and relation has blocks , therefore , in the best case , only ________ block transfers would be required for . An ideal hash function is ________ and ________ , the former require that each bucket is assigned the same number of search-key values form the set of all possible values. To generate query-evaluation plans for an expression we have to generate logically equivalent expressions using ________ . Consider a +- tree of order ,if there are search-key values in the file , the path form the root to the leaf mode is no longer than ________ . A transaction has the following properties: ________ , ________ , isolation and durability. When the final statement of a transaction has been executed , the transaction enters the ________ committed state . After a transaction has been rolled back and the database has been restored to its previous state , the transaction enter the ________ state . A schedule is ________ if a transaction in needs a data item previously written by a transaction , then the commit operation of appears before the commit operation of . __