Additions and deletions to create mysql database, creating tables and fields

mysql

• mysql is a relational database, used, need to create a database (database) in advance, the data table (table) do not need to create in advance by object-relational mapping framework can be resolved.
• Database (database)
• Displays the version of the database:
  • select version();
• Creating a database
  • create database database name of the charset = utf8;
  • create database goods charser=utf8;
• Statement to check the database created
• show create database database name;
• View current database used
• select database();
• Use Database
• use the database name
• use goods;
• Delete Database
• drop database database name;
• data sheet:
• View all the tables in the current database
• show tables;
• Create a table
• auto_increment means the automatic growth, not null representation can not be null, primary key primary key represents the default default key
• create table students(id int ,name varchar(30));
• sql statement to view the table created;
• show create table students;

create table students(
        id int unsigned not null auto_increment primary key,
        name varchar(30),
        age tinyint unsigned default 0,
        high decimal(5,2),
        gender enum("男", "女", "中性", "保密") default "保密",
        cls_id int unsigned
    );

• Adding fields and removing fields

alter table students add bith date;
alter table students drop high;
alter table 表名 add 字段 约束；
alter table 表名 drop 字段；

• Constraints modify the field of

alter table students modify birthday datatime;

• Name and constraints modify the field

alter talbe students change birthday birth date default "200-01-01";

Delete Data Sheet

drop table 表名
drop database 数据库名，删除数据库同时也把表删除了

• mysql modify the table name

rename table table1 to table2;
rename table class to classes;