1.查看数据库编码格式

mysql> show variables like 'character_set_database';

 2.查看数据表的编码格式

mysql> show create table 
     
      ;
     

 3.创建数据库时指定数据库的字符集

mysql>create database 
     
       character set utf8;
     

4.创建数据表时指定数据表的编码格式

create table tb_books (    name varchar(128) not null,    price double not null,    bookCount int not null,    author varchar(128) not null ) default charset = utf8;

5.修改数据库的编码格式

mysql>alter database 
     
       character set utf8;
     

6.修改数据表格编码格式

mysql>alter table 
     
       character set utf8;
     

7.修改字段编码格式

mysql>alter table 
     
       change 
       
        
        
          character set utf8;mysql>alter table user change username username varchar(128) character set utf8 not null;
        
       
      
     

 8.添加外键

mysql>alter table tb_product add constraint fk_1 foreign key(factoryid) references tb_factory(factoryid);mysql>alter table 
     
       add constraint 
      
        foreign key
       
         REFERENCES 
        
         
          ;
         
        
       
      
     

9.删除外键

mysql>alter table tb_people drop foreign key fk_1;mysql>alter table 
     
       drop foreign key 
      
       ;