PartTwoDatabaseDesign課件.pptVIP

March 2008 Database System Concepts - Chapter6 Database Design and E-R Model Part Two  Database Design Chapter 6  Database Design and E-R Model Four Parts in Chapter 6 Part 1. DB design phases (§6.1) requirement analysis, conceptual design, logical design, physical design Part 2. The Entity-Relationship Model basic E-R model modeling elements (§6.2.1-6.2.3): entity sets, relationship sets, attributes constraints (§6.3.1-6.3.3): mapping cardinality, keys, participation constraint (§6.6) weak entity sets Four Parts in Chapter 6 extended E-R model (§6.7) (§6.7.1-6.7.4) induce OO features into E-R model , that is, specialization, generalization, attributes inheritance, constraints on genelization (6.7.5) aggregation: relationship among relationships (§6.4) entity-relationship diagrams (§6.8) E-R diagram, i.e., conceptual design, for banking enterprise Four Parts in Chapter 6 (cont.) Part 3. E-R design issues (§6.5) when applying E-R model to model the objects in real worlds, some issues (considerations and principles) should be addressed, to guarantee DBS effectiveness and efficiency for data Part 4. Reduction to relational schemas (§6.9 ) mapping elements in E-R model to that in relational models, i.e. conceptual schema ?initial logical schema §6.1 Overview of the Design Process Database design consists of two sequential phases analyzing of user requirements what data should be stored in the database what operations/transaction, such as insert, delete, update and retrieve are needed to conducted on these data designing of DB schemas , in accordance with the three-level of data abstract (refer to Fig. 1.1) conceptual design logical design, at the logical level and view level physical design, at the physical level refer to Fig.1.0.1 6.1 Overview of the Design Process (cont.) 数据库应用系统DBAS设计 DB, DBMS, users, application programs refer to Fig. 6.0.2 电信网管系统示意图 DBAS设计 refer to Fig. 6.0.3 DBAS 生命周期模型 参照软件工程中软件开发瀑布模型原理，DBAS的生命周期由项目规划、需求分析、系统设计、实