MySQL Database basic use

1. View the database encoding format

0./**-All rights-**/
GRANT all on Epet to ' epetadmin ' @localhost identified by ' 1234 ';

Mysql> Show variables like ' character_set_database ';

2. View the encoding format of the data table

Mysql> Show CREATE table < table name >;

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

Mysql>create databases < 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 () is not NULL,

Price double is not NULL,

Bookcount int NOT NULL,

Author varchar () NOT NULL) default CharSet = UTF8;

5. Modify the encoding format of the database

Mysql>alter databases < database name > character set UTF8;

6. Modify the data table encoding format

Mysql>alter Table < name > character set UTF8;

7. Modify the field encoding format

Mysql>alter Table < name > Change < Field name > < Field name > < type > Character set UTF8;

Mysql>alter Table User change username username varchar character set UTF8 NOT null;

8. Add a FOREIGN key

Mysql>alter table tb_product Add constraint fk_1 foreign key (Factoryid) references tb_factory (Factoryid);

Mysql>alter table < table name > Add constraint < foreign key name > Foreign key< Field name > REFERENCES < outer table name >< field name >;

9. Delete foreign keys

Mysql>alter table tb_people drop foreign key fk_1;

Mysql>alter table < table name > drop FOREIGN Key < foreign key name >;

10. Query the new self-increment subscript

SELECT @ @IDENTITY

MySQL database basic use