Summary of review questions of database principle and application

Summary of review questions of database principle and application

One, the individual choice question (each small question 1 points, altogether 20 points)

1. In the three modes of the database, the data is actually stored () a. Internal Mode B. Mode c. external mode D. All three store data

2, in the database of three modes ()

A. Internal mode has only one, while mode and outer mode can have multiple

B. There is only one mode, while the inner and outer modes can have multiple

C. There is only one mode and internal mode, and the outer mode can have multiple

D. There is only one

3, about the mode, the following statement is wrong ()

A. Global logical structure of a database Description B. Framework of the database

C. Collections of a set of patterns D. data in a database

4, the following four is incorrect in the statement ()

A. Database reduces data redundancy b. Data in the database can be shared

C. Database avoids duplication of all data D. Database with high data independence

5, the company has a number of departments and a number of staff, each employee can only belong to one department, a department can have more than one staff, from the staff to the Department of contact type is ()

A. Many-to-many B. One-to-several C. Multi-pair D.

6, the following four items, the query must be optimized is ()

A. Relational database B. Mesh database c. Hierarchical database D. Non-relational model

7. The operation that cannot be completed on the view is ()

A. Updating views B. querying

C. Defining a new base table on a view D. Defining a new view on a view

8. Among the three components of the relational data model, excluding ()

A. Integrity rules B. Data structure c. recovery D. Operations

9, the following four items, not belonging to the characteristics of the relational database is ()

A. Data redundancy small B. Data independence high C. Data sharing good D. Multiuser access

10. Possible problems with concurrent operation of the database include ()

A. Missing update B. Data independence increased c. Use of illegal users d. increased data redundancy

11, in the basic SQL language, can not be implemented ()

A. Defining A View B. Defining a base table C. Query views and base tables D. concurrency control

12, the following items belong to the characteristics of the database system is ()

A storage capacity of large B processing speed C data sharing D easy to use

13, the E-R model that expresses the logical connection between entities, is the database ()

A conceptual Model B logical model C external model D physical model

14, after the "projection" operation on the relationship, the number of tuples and the number of tuples in the original relationship ()

A the same B less than the meta relationship C is greater than the original relationship D is not greater than the original relationship

15, the relationship "sales" includes the store name and the product name and other attributes, query the sale of three products at the same time the store name, should be taken in relation to algebra operations ()

A Select B projection C except for the D connection

16, in the bookstore "Sales" table, defined: ISBN, author number, publishing house number, price and other attributes, its main code should be ()

A ISBN B author C publishing house Number D ISBN, author number

17, the following about the SQL language narrative, the error is ()

A. The SQL language vocabulary is limited and easy to learn.

B. The SQL language has a flexible and powerful query function.

C. The SQL language is a non-procedural language.

D. Strong SQL language capability to meet all application requirements

18. A process that represents concurrent processing of multiple transactions, called a transaction ()

A permanent B parallelism C serialization D Isolation

19. The function of primary KEY in the SQL language is ()

A. Defining a master code b. Defining an external code c. Defining a reference table for a department code D. Determining the main code type

20. Database triggers are used to define ()

A. Security controls B. Integrity constraints C. Data Access range D. Methods of deadlock handling

Second, fill in the blanks (this big question a total of 20 small questions, each topic 1 points, a total of 20 points)

1, from the point of view of the relationship normalization theory, one of the four aspects that satisfies the 1NF relationship is: Data redundancy, modification anomaly, inserting exception and so on.

2. If all attributes that satisfy a 1NF relationship are combined to form a keyword, the most satisfying paradigm for the relationship is (in the 1NF, 2NF, 3NF range).

3. Data independence is divided into ----------and------

4. The language provided by the DBMS for manipulating the database is referred to as the English abbreviation for

5, there is a relationship between the various attributes ,------,----,------- These three types of links.

6, a relational pattern of Y (x1,x2,x3,x4), assuming that the relationship has the following function dependency: x1→x2,x1→x3,x1→x4, the relationship belongs to the 2 paradigm, because it has a full dependency

7, the database of special relational operations including selection , connection and projection of three.

8. The join operation is to generate a new relationship between two or more relationships based on the join condition.

9, there is a student relationship, the key word for the study number, there is a curriculum relationship, the key word for the course number, and an elective relationship, the key word for the study number and the course number of the combination, the student number and the course number is the main, outside the key word .

10, if the attribute x and Y is a connection of 1:1, then the relationship between X and Y is called a one-on, x<ày .

11, in the same relationship model, if there is a non-trivial function dependent x→y,y→z, and YX, is called z_____? ___x.

12. Attributes contained in any of the candidate keywords are called primary properties , and properties that are not included in any of the candidate keywords are called non-primary properties .

13. The first four stages of database application system design are demand Analysis , conceptual structure Analysis , and ___ Logical Structure analysis ________. Physical Structure Analysis

14. In the E-R model, the entity is represented by the _____ rectangle box, the property is represented by the ___ Ellipse _________ box, and the relation between entities is represented by the _____ Diamond _______ box.

15, a student can borrow more books at the same time, a book can only be borrowed by one student, between students and books for ___ a pair of more _________ contact.

16. The tuples and attributes in the relationship correspond to ____ rows (records) ________ and _ Columns (fields) ___________ in the two-dimensional table respectively.

17, the system uses a certain range of data in the database to block the purpose is to avoid concurrency control .

18, in the E-r diagram, use a rectangular box to represent the entity , with a diamond-shaped box to represent the relationship , with an oval box to represent the property .

19, the DBMS concurrency control unit for the transaction .

20, in the SQL language structure, the basic table has the corresponding storage file, and the view does not have the corresponding storage file.

Three, Jane answer questions (5 points per small question, a total of 10)

1. What are the functions of database management system?

2. How do you ensure database security by defining views and access controls? Use the SQL language to illustrate.

3 Department: Including department number, department name, office. There are multiple employees in each department.

Employees: including employee number, name, gender, age, title, professional, resume.

Resume: Including start time, end time, work unit, hold position.

Project: Including project number, project name, project funding, project source, responsible person.

Each employee can participate in multiple projects, each of which can be attended by multiple employees. Requirements:

1) Draw an entity association diagram that expresses this problem.

2) write out the logical model of the relational database.

3) Draw a data structure diagram.

4) write the definition of database and table in SQL language.

Reference answer

One, the single choice question (this big question altogether 20 small questions, each small question 1 points, total 20 points)

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Three, simple answer

1,. What are the functions of the database management system?

A: The database management System (DBMS) is a data management software located between the operating system and the user, and its main functions include the following aspects:

• Data definition functions The DBMS provides data Description language (DDL) that users can use to define data.

· Data manipulation Capabilities The DBMS also provides data manipulation language (DML), which implements basic operations on the database: query, INSERT, delete, and modify.

· operation Management of database This is a core part of DBMS runtime, which includes development control, security check, integrity constraint checking and execution, database content maintenance and so on.

· database establishment and maintenance functions it includes input and conversion of initial data of database, database dump and recovery, database reorganization function and performance monitoring and analysis function, etc.

3. How do you ensure database security by defining views and access controls? Use the SQL language to illustrate.

Views provide secure protection of confidential data. With the view mechanism, it is possible to define different views of different users when designing a database application, so that confidential data is not present in the user view of the data, so that the view mechanism automatically provides security protection for confidential data. For example, the student table covers the student data for three departments, where you can define three views, each containing only one department of student data, and only allow students from each department to query the student view of their department.

Example: Establish a view of students in the information system.

CREATE VIEW is_student

As

SELECT Sno, Sname, Sage

From Student

WHERE sdept= ' is ';

Database security refers to the protection of the database, to prevent illegal use caused by the data leakage and destruction. The main measures to ensure data security in database system are access control, that is, to specify the actions that different users can perform for different data objects, and to control the user to access only the data that he has permission to access. The operational power that different users have over different data is determined by the DBA and the creator of the table (the owner of the table) depending on the situation, and the SQL language provides a means for the DBA and the owner of the table to define and reclaim this power.

Example: Grant the query student table permission to the user U1.

GRANT SELECT on TABLE Student to U1;

4:

Summary of review questions of database principle and application