Basic learning of SQL Server -- creating databases and tables with code

１. After the connection is successful, the following page appears , Then, the first step of our study is to build a database and table

２. Understand the foundation before establishing SQL Language

SQL Language is a collection of DDL、DML、DCL Integrated database language .
１）DDL Sentence guide word ：Create（ establish ）、Alter( modify )、Drop（ revoke ）
Definition and deletion of patterns , Including definition Database,Table,View,Index, Integrity constraints, etc , It also includes defining objects （RowType Line object ,Type List objects ）
２）DML Sentence guide word ：Insert、Delete、Update,Select
Various methods of update and retrieval operation , For example, enter the record directly , From the other Table（ from SubQuery establish ） Input .2. Retrieval of various complex conditions , Such as connection search 、 Fuzzy search 、 Group search 、 Nested search, etc .3. Various aggregation operations , Averaging 、 Sum up 、.. etc. , Group aggregation , Group filtering, etc
３）DCL Sentence guide word ：Grant,Revoke
Security control ： Authorization and revocation of authorization

３. To build a database, you need to define the database and tables （ Use DDL）, Append tuples... To the table （ Use DML）

DDL：Data　Definition　Language

１） Create database DB　　 The sentence used starts with ：Create　Database

２） establish DB Medium Table（ Defining relational patterns ）　 Statement start ：Create　Table

notes ： A table has at least one column

  Frequently used data types

4. Example ： Create course learning database SCT

notes ：DBMS Create a SCT data

First step ： Click new query , Input

create　database　SCT;

End of sentence   Semicolon in English   Add it or not Watching habits

The second step ： Click execute （ Under new query ）, The prompt appears ： The command completed successfully

The third step ： Select the left side     database , Right click —— Select refresh —— appear SCT database    

Database establishment is complete

5. establish SCT Table under database

Right click SCT database , Click new query , New SQLQuery2.sql

Enter After the command to create a table —— Click execute

Code ：

create Table Student(
    S# char(8) not null,
    Sname char(10),
    Ssex char(2),
    Sage integer,
    D# char(2),
    Sclass char(6),
)

create Table Course(
    C# char(3),
    Cname char(12),
    Chours integer,
    Credit float(1),
    T# char(3),
)

single click SCT—— Refresh —— Two newly created tables appear in the table ,SCT The following table was created successfully

6. To save the code  

single click Save button   , Store the files in the folder you define

7. Append tuple of table

（ Tuples can be understood as rows of a table ）

Yes Student surface , Add Zhang San's information （ The previous code to create the table has been run , Therefore, the newly written code can be locally selected , Click on —— perform ）

 8. Check the contents of the table

Select... On the left Student surface —— Right click —— Edit the first two hundred lines

  You can add or delete tuples directly in the table

9. Looking at the table with code

Select * from Student

The screenshot of the knowledge points in the article comes from ： Netease public class app—— Database system （ Harbin Institute of Technology Speaker ： Mr. Zhan Dechen ）