Application stage BUPT "Database Principles and Applications" Job BELT answer

A multiple-choice (a total of 10 small problem, a total 100.0 points) 1. In the following statements about the relationship, the error is _____. Table A. any two rows can have the same value B. Table arbitrary two can have the same C. order of rows in the table does not matter D. It does not matter the order listed in the table Knowledge points: Relations Relation Student answers: [B;] Score: [10] Questions scores: 10.0 2. The narrative about primary keys below the right is ______. A. different recording may have duplicate primary key values ​​or a null value B. a primary key of the table may be one or more fields C. In a primary key table may be only one field D. The data type of the primary key of the table must be defined as automatic number or text Knowledge points: Key code Student answers: [B;] Score: [10] Questions scores: 10.0 3. relational database, the realization of the link between the entities is ______ between the table and the table through. A. Public Index B. Public storage C. Public tuple D. Public Properties Knowledge points: Contact relational database Student answers: [D;] Score: [10] Questions scores: 10.0 4. define the foreign key is implemented ______. A. entity integrity B. referential integrity C. User-defined integrity D. entity integrity, referential integrity and the integrity of the user-defined Knowledge points: Relational integrity rules Student answers: [B;] Score: [10] Questions scores: 10.0 5. There is a relationship: Student (Student ID, name, academic departments), the provisions of range of student number is a string of eight digits, the rule belongs to _____. A. entity integrity rule B. referential integrity constraints C. User-defined integrity rules D. keywords integrity constraints Knowledge points: Relational integrity rules Student answers: [C;] Score: [10] Questions scores: 10.0 6. ______ on the right is a conceptual model of a database parlance. A. depends on the DBMS, hardware independent B. independent of hardware and DBMS C. depends on the operating system, independent of the DBMS D. independent of the user's needs Knowledge points: Database Design Process Student answers: [B;] Score: [10] Questions scores: 10.0 7. ER FIG _______ is a visual representation of the tool. A. Structure Data Model B. Relational Data Model C. logical data model D. hierarchical and network models Knowledge points: Database Design Process Student answers: [B;] Score: [10] Questions scores: 10.0 8. The database is divided three mode architecture, ______ is conducive to maintaining the database. A. data independence B. Data Security C. standardized structure D. operational feasibility Knowledge points: Database architecture Student answers: [A;] Score: [10] Questions scores: 10.0 Provided R & lt 9. (U) is the relational model to the attribute set U, X, Y is a subset of U. If for any R (U) of a possible relationship r, r can not exist in two equal groups on the meta attribute values ​​of X, Y and attribute values ​​in the range, called ________. A. Y函数依赖于X B. Y对X完全函数依赖 C. X为U的候选码 D. R属于2NF 知识点: 关系规范化 学生答案: [A;] 得分: [10] 试题分值: 10.0 10. 设有关系W（工号，姓名，工种，定额），将其规范化到第三范式正确的答案是______。 A. W1（工号，姓名），W2（工种，定额） B. W1（工号，定额），W2（姓名，工种） C. W1（工号，姓名，工种），W2（工种，定额） D. W1（工号，工种，定额），W2（工号，姓名） 知识点: 关系规范化 学生答案: [D;] 得分: [10] 试题分值: 10.0

读书和健身总有一个在路上