COURSE_FEE将是非素数属性, 因为它不属于一个唯一的候选键{STUD_NO, COURSE_NO}; 但是, COURSE_NO-> COURSE_FEE, 即COURSE_FEE依赖于COURSE_NO, 它是候选密钥的适当子集。非质数属性COURSE_FEE依赖于候选键的适当子集, 这是部分依赖关系, 因此此关系不在2NF中。 要将以上关系转换为2NF, 我们需要将表拆分...
The DBMS course designed by Tutorials Point will help you master crucial concepts like the E-R model, relation model, relational database design, functional dependencies, normalization, transaction management, concurrency control, recovery, reliability and storage, file structure, and many other facets....
e.g. 可保存一个包含course和prereq所有属性的关系以避免计算连接,提高性能。(代价是用于保持冗余数据一致性的额外工作); 更好的方法:可使用规范化的模式将course和prereq的连接作为物化视图额外存储。 4.其他设计问题 时态数据建模 时态数据(temporal data):具有关联的时间段的数据,在时间段之间数据有效(valid)。 ...
If you manage studies alongside your 9 to 5 job, this Full Stack Software Development Bootcamp by upGrad will be the perfect option! This comprehensive course will give you the necessary knowledge to build an efficient database management system. Full Stack Development by IITBIf...
Course数据库表(部分数据信息)如下: (测试用例) 1 51200437932006周泽学计算机科学技术学院计算机科学与技术262 1 52200524442006杨毅计算机科学技术学院计算机科学与技术512 1 53200607662006史海亮计算机科学技术学院计算机科学与技术335 1 54200607692006周贵宾计算机科学技术学院计算机科学与技术560 1 55200611832006董超计算机科学...
(Discussed later in the course in greater detail) Phases of database design Database designing for a real-world application starts from capturing the requirements to physical implementation using DBMS software which consists of following steps shown below: Conceptual Design: The requirements of database...
Beise, C. (2006). Revisiting database resource choice: A framework for DBMS course tool selection. Pro- ceedings of the Twelfth Americas Conference on Information Systems, Acapulco, Mexico, 2139-2144 Retrieved November 18, 2012 from http://aisel.aisnet.org/amcis2006/266/...
StudentId Name Course1 course2101Raj Mathematics Chemistry102Nilesh Chemistry103Sanu Physics Chemistry 为了确保这个模型是第一范式,我们将课程元组(上一个示例)拆分为 course1 和 course2 以将我们的课程信息作为原子实体保存,以便没有行包含多个课程。没有重复的行。
实体集course 由course_id唯一标识; (i.e. 不同course的section可能会有相同的sec_id、year和semester。) 联系集sec_course关联section和course。 分析: 因为section已有属性course_id,sec_course中信息冗余。 如果删除联系sec_course会使section和course的联系隐含于一个属性中,不合适。
(Discussed later in the course in greater detail) Phases of database design Database designing for a real-world application starts from capturing the requirements to physical implementation using DBMS software which consists of following steps shown below: Conceptual Design: The requirements of database...