SSD7数据库系统选择题答案VIP专享VIP免费

Multiple-Choice Quiz 1 1. An E-Commerce system consists of the following components. Which of these same components must be included in a database? (c) The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. A database must include a collection of programs that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains. A database must include a collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) I, II, and III (b) I and II only (c) I only (d) II only 2. An E-Commerce database contains data about customers, products, orders, system response times, etc. Which of the following can be specified as integrity constraints in an E-Commerce database system? (d) No two products can have the same product ID. The DBMS response time for all Web requests should be at most 2 seconds. A customer order cannot have more than one shipping address. (a) I only (b) I, II, and III (c) I and II only (d) I and III only Feedback: The constraints I, II and III specify the application semantics of the data captured in the E-Commerce database. Constraint III, although it seems contrary to common sense, is not something that can be prohibited by the DBMS because the DBMS is general purpose. The response time of the DBMS cannot be enforced by the DBMS. It depends on factors such the processor speed, memory available, etc. 3. An E-Commerce system consists of the following components. Which of these...