MySQL Create a table statement

1Show variables like 'character_set_client'; #查询字符集2 show databases; #列出所有的服务器上的数据库alter3 Create Database if  not existstest; #创建一个数据库4 Drop DatabaseFK; #删除数据库5Show tables fromtest; #显示一个数据库中的表6  Usetest;7 8 Create TableTb_dept (9Idint Primary Keyauto_increment, #部门编号 shaping primary key self-growthTenNamevarchar( -), #部门名称 OneDescriptionvarchar( -) #描述 A ); -  -Show tables fromtest; the  - desctb_dept; #查看表信息 -  -ShowCreate Tabletb_dept; +  -  Usetest; + #员工表 A Create TableTb_emp ( atIdint Primary Keyauto_increment, #auto_increment只是MySQL特有的 -Namevarchar( -), -Sexvarchar(2), -Ageint, -Addressvarchar( $), -Emailvarchar( -) in ); -  to Drop Tabletb_dept; + #修改列类型 - #注意: It is not possible to modify it under any circumstances, the #只有当字段只包含空值时才可以修改.  * Alter TableTb_emp Modify Sexvarchar(4); $ #增加列Panax Notoginseng Alter TableTb_empAddTelvarchar( A); - #删除列 the Alter TableTb_empDropTel; + Alter TableTb_empDrop columnTel; A #列改名 the Alter TableTb_emp Change Name emp_namevarchar( -); + #更改表名 - Alter Tabletb_emp rename emp; $RenameTableEmp totb_emp; $  - Insert  intoDept_emp (Name,sex,age,address,email)Values("',"',"',"',"'); -  the #约束 - #是在表上强制执行地数据校验规则, mainly used to ensure database integrityWuyi /* the Not null - Unique uniqueness Key Tb_depttb_dept Wu PRIMARY Key - foreign key foreign key About Check Checks $ */ -  - Create TableTb_emp ( -Idint Primary KeyAuto_increment, ANamevarchar( -), +Sexvarchar(2)default'male' Check(Sex='male'orSex='female'), #表级写法check does not work in MySQL theAgeint, -Addressvarchar( $), $Emailvarchar( -)Unique, thedept_idint,#Referencestb_dept (ID) #表级写法外键不起作用 the constraint Foreign KeyFk_emp (dept_id)Referencestb_dept (ID) the ); the  - #创建表之后在添加 in Alter TableTb_empAdd constraint Foreign KeyFk_emp (dept_id)ReferencesTb_dept (ID);

MySQL Create a table statement