MySQL joins columns, changes columns, deletes columns
ALTER table: Add, change, delete table columns, constraints and other table definitions.
- View column: Desc table name;
- Change table name: ALTER TABLE T_book Rename to BBB;
- Add column: ALTER TABLE name add column name varchar (30);
- Delete column: ALTER TABLE table name drop column name;
- Change Column name mysql:alter table BBB change nnnnn hh int;
- Change the column name sqlserver:exec sp_rename ' t_student.name ', ' nn ', ' column ';
- Change Column name oracle:lter table BBB Rename column nnnnn to HH int;
- Change column properties: ALTER TABLE T_book modify name varchar (22);
Sp_rename:sqlserver built-in stored procedures, with the definition of the change table.
MySQL view constraint, add constraint, delete constraint join column, alter COLUMN, delete column
- View field information for table: DESC table name;
- View all information about the table: Show create table table name;
- Add PRIMARY KEY constraint: ALTER TABLE name add constraint primary key (Shape: Pk_ table name) primary key table name (primary key field);
- Add FOREIGN KEY constraint: ALTER TABLE from TABLE ADD constraint foreign key (shape: Fk_ from Table _ Main Table) foreign key from table (foreign key field) references Main Table (primary key field);
- Delete PRIMARY KEY constraint: ALTER TABLE name drop PRIMARY key;
- Delete FOREIGN KEY constraint: ALTER TABLE name drop FOREIGN key foreign key (distinguish uppercase and lowercase);
- change table name: ALTER TABLE T_book Rename to BBB;
- add column: ALTER TABLE name add column name varchar (+);
- delete column: ALTER TABLE table name drop column name;
- change column name Mysql:alter table bbb changes nnnnn hh int;
- change column name sqlserver:exec sp_rename ' T_student.name ', ' NN ', ' column ';
- change column name oracle:alter table BBB Rename column nnnnn to HH int;
- Change column properties: ALTER TABLE T_book modify name varchar;
Sp_rename:sqlserver built-in stored procedures, with the definition of the change table.
