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A brief introduction to the database of tyut Taiyuan University of technology in previous years
2022-07-06 13:12:00 【Lala Lulu^_^】
The brief questions of previous years do not apply to this year , You should also recite the short answer questions in the two question banks in Baidu online disk that I share ( Link to the first blog in the database )
Chapter one
1. What is the definition of a database ?
The database is stored in the computer for a long time 、 organized 、 A collection of large amounts of data that can be shared .
2. What are the main functions of database management system
(1) Data definition function ,
(2) Organization of data 、 Storage and management ,
(3) Data manipulation function ,
(4) Transaction management and operation management of database ,
(5) The establishment and maintenance of database ,
(6) Other features .
3. What are the three elements of the data model ?
data structure 、 Data operation and data integrity constraints constitute the three elements of the data model .
4. What are the data operations in the database ?
Data operations in the database include inserting 、 modify 、 Delete and query .
5. What are the three types of connections between entities ?
The connection between entities includes one-to-one connection 、 There are three types of one to many connections and many to many connections .
6. What are the commonly used logical data models in the field of database ?
The logical data model commonly used in the field of database is hierarchical model 、 Mesh model 、 relational model 、 Object oriented model, etc .
7. What are the components of the database system ?
A database system consists of a database 、 Database management system 、 Application system and database administrator .
8. Three level structure of database system ?
The three-level schema structure of database system refers to the external schema 、 Pattern 、 Internal mode
9. Database management system
Database management system (Database Management System,DBMS) It is a layer of data management software between the user and the operating system , Provide users or applications with access to the database , Including the establishment of database 、 Inquire about 、 Update and various data control .DBMS Always based on some kind of data , It can be divided into hierarchical models 、 Mesh model 、 relational model 、 Object oriented model, etc DBMS
10. Data independence refers to the mutual independence between applications and data , Unaffected . Data independence is divided into physical data independence and logical data independence .(1) Logical independence : When the pattern changes , The database administrator modifies the external schema / Pattern mapping , Keep the outer mode unchanged , So the application doesn't have to be modified , Ensure the logical independence of data and program , The logical independence of data .(2) Physical independence : When the storage structure of the database changes , The database administrator modifies the schema / Inner pattern mapping , Leave the mode unchanged , Application is not affected . Ensure the physical independence of data and program , Physical independence of data
Chapter two
1. What are the three components of the relational model ?
The relational model consists of relational data structure 、 Relationship operation and relationship integrity constraints consist of three parts .
2. The integrity of relational models can be roughly divided into three categories ?
Constraints on the integrity of relationships include primary key constraints 、 Foreign key constraints and user-defined integrity constraints .
3. Which relational query operations are provided in relational algebra ?
Queries in relational algebra include the union of Relations 、 hand over 、 Bad 、 Cartesian product 、 choice 、 Projection 、 Operations such as connection and division .
The third chapter
1.SQL What are the commonly used sentences in language ?
SQL Language set data definitions 、 Data query 、 Data manipulation and data control functions are integrated , Its main operation statements include CREATE、ALTER、DROP、INSERT、UPDATE、DELETE、SELECT、GRANT、REVOKE etc. .
2.SQL Which common aggregation functions are provided in ? How they are used ?
SQL Some aggregate functions are provided in , Except for statistical database data , Include COUNT、AVG、SUM、 MAX、MIN etc. , COUNT(*) Beyond usage , Null values are ignored in Statistics , Use DISTINCT Options can be ignored Statistics of duplicate data . Aggregate functions can only be used for SELECT Clause and HAVING Clause .
3. What is a join query ? How connection queries specify connection conditions ?
If a query involves two tables at the same time , It is called join query . The connection conditions of connection query can be found in WHERE Clause is specified by a comparison operation , Or in the FROM Clause specifies both the connection method and the connection condition .
4. What is subquery ? Use in WHERE There are several ways to call subqueries in Clause ?
Subquery is also called nested query , Is nested in SELECT、INSERT、UPDATE、DELETE And so on Of SELECT Query statement . Use it more often WHERE clause , Use the results of subqueries as search criteria . stay Where There are several ways to use subqueries in Clauses : from IN Export sub query 、 The subquery is derived from the comparison operator 、 from EXISTS Export sub query .
The fifth chapter
1. What is database integrity ? What are the types of relational database integrity ?
Data integrity refers to the logical consistency and correctness of the data in the database .
The integrity of relational database includes entity integrity 、 Reference integrity and user-defined integrity .
2. The five common constraints are : Primary key constraint , Foreign key constraints , Non empty constraint , Unique constraint , Check constraint !
Chapter vii.
1. What aspects of technology and knowledge are involved in database design ?
Database design involves many aspects of technology and knowledge , Including the basic knowledge of computer 、 Programming methods and skills 、 Principles and methods of software engineering 、 Basic knowledge of databases 、 Knowledge of database design technology and application fields .
2. What are the stages of database design ?
Database design includes requirements analysis 、 Conceptual structural design 、 Logical structure design 、 Physical structure design 、 There are six stages of database implementation and database operation and maintenance .
3. establish E-R Which steps does the diagram include ?
establish E-R The process of drawing includes :(1) First, determine the body shape ,(2) Determine the type of contact ,(3) Put the solid body Combined with connection E-R chart ,(4) Determine the attributes of entity type and connection
Fill in the blanks in previous years
- The database is stored in the computer for a long time , organized , A collection of large amounts of data that can be shared .
- The functions of the database system include : Definition of database , Organization, storage and management of database , Database manipulation , Database management and operation management , The establishment and maintenance of database
- Database manipulation includes inserting , Delete , Modification and query
- data structure , Data manipulation and integrity constraints constitute the three elements of the data model
- The practice between entities includes one-on-one contact , One to many connection , Many to many contact
- The logical data models commonly used in database systems are hierarchical models , Mesh model , relational model , Object oriented model, etc
- A database system consists of a database 、 Database management system 、 Application system and database administrator .
- The three-level schema structure of database system refers to schema 、 Inside mode and outside mode .
- Database management system (Database Management System,DBMS) It is located between the user and the operating system
A layer of data management software , Provide users or applications with access to the database , Including the establishment of database 、
Inquire about 、 Update and various data control .DBMS Always based on some kind of data , It can be divided into hierarchical models 、 Mesh model 、 relational model 、 Object oriented model, etc DBMS.
10. Data independence refers to the mutual independence between applications and data , Unaffected . Data independence is divided into physical data independence And logical data independence .
(1) Logical independence : When the pattern changes , The database administrator modifies the external schema / Pattern mapping , Make external mode remain unchanged , So the application doesn't have to be modified , Ensure the logical independence of data and program , Abbreviation: Logic of data independence .
(2) Physical independence : When the storage structure of the database changes , The database administrator modifies the schema / Inner pattern mapping , Make the mode secure Stay the same , Application is not affected . Ensure the physical independence of data and program , Physical independence of data .
11. The relational model consists of relational data structure 、 Relationship operation and relationship integrity constraints consist of three parts .
12. Relationship integrity constraints include primary key constraints 、 Foreign key constraints and user-defined integrity constraints .
13. Queries in relational algebra include the union of Relations 、 hand over 、 Bad 、 Cartesian product 、 choice 、 Projection 、 Operations such as connection and division
14. SQL Language set data query 、 Data manipulation 、 Data definition and data control functions are integrated , Its main operating language
Sentence includes CREATE、ALTER、DROP、INSERT、UPDATE、DELETE、SELECT、GRANT、
REVOKE etc. .
15. SQL Some aggregate functions are provided in , Used for statistical database data , Include COUNT、AVG、SUM、MAX、 MIN etc. , except COUNT(*) Beyond usage , Null values are ignored in Statistics , Use DISTINCT Options can be ignored
Statistics of duplicate data . The number of aggregated rows can only be used for SELECT Clause and HAVING Clause .
16. If a query involves two tables at the same time , It is called join query . The connection conditions of connection query can be found in WHERE clause Specify by a comparison operation , Or in the FROM Clause specifies both the connection method and the connection condition .
17. Subquery is also called nested query , Is nested in SELECT、INSERT、UPDATE、DELETE Wait for SELECT Query statement . Use it more often WHERE clause , Use the results of subqueries as search criteria . stay Where
There are several ways to use subqueries in Clauses : from IN Export sub query 、 The subquery is derived from the comparison operator 、 from EXISTS Export sub query .
18. The security of database means to protect database , Prevent data leakage caused by users' illegal use of the database 、 To alter or destroy .
The commonly used security control methods in database systems include technology, including user identification and authentication 、 Access control 、 Define views 、 Audit 、 Count According to encryption .
19. Data integrity refers to the logical consistency and accuracy of the data in the database .
The integrity of relational database includes entity integrity 、 Reference integrity and user-defined integrity .
20. trigger (Trigger) It is a kind of special event driven stored procedure defined by the user on the relational table . Trigger
The device consists of inserting the table 、 Modify and delete event activation .
21. Database design includes requirements analysis 、 Conceptual structural design 、 Logical structure design 、 Physical structure design 、 database
Implementation and database operation and maintenance in six stages .
22. establish E-R The process of drawing includes :(1) First, determine the body shape ,(2) Determine the type of contact ,(3) Put the solid body
Combined with connection E-R chart ,(4) Determine the attributes of entity type and connection
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