View the encoding format of mysql

1. View the database encoding format

show variables like 'character_set_database';

 2. Check the encoding format of the data sheet

show create table <表名>;

3. Specify the character set of the database when creating the database

create  database  < database name >  character  set utf8;

4. Specify the encoding format of the data table when creating the data table

create table tb_books (
    name varchar(45) not null,
    price double not null,
    bookCount int not null,
    author varchar(45) not null ) default charset = utf8;

5. Modify the encoding format of the database

alter  database  < database name >  character  set utf8;

6. Modify the data table encoding format

alter table <表名> character set utf8;

7. Modify the field encoding format

alter  table  < table name > change < field name >  < field name >  < type >  character  set utf8;

alter table user change username username varchar(20) character set utf8 not null;

8. Add foreign keys

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

9. Delete foreign keys

alter  table tb_people drop  foreign  key fk_1;
alter  table  <表 名>  drop  foreign  key  <外 键 名> ;