MySQL的增删查改语句用法示例总结

alter table tablename add colname type not null default '0′;

  alter table mmanapp_mmanmedia add appid_id integer not null default 372;

  alter table tablename drop column colname;

  alter table mmanapp_mmanmedia drop column appid_id;

ALTER TABLE yourtablename  ADD [CONSTRAINT symbol] FOREIGN KEY [id] (index_col_name, …)  REFERENCES tbl_name (index_col_name, …)  [ON DELETE {RESTRICT | CASCADE | SET NULL | NO ACTION}]  [ON UPDATE {RESTRICT | CASCADE | SET NULL | NO ACTION}]

ALTER TABLE mmanapp_mmanmedia ADD CONSTRAINT fk_mdappid FOREIGN KEY(appid_id)

  ALTER TABLE yourtablename DROP FOREIGN KEY fk_symbol;

 ALTER TABLE mmanapp_mmanmedia DROP FOREIGN KEY fk_mdappid

alter table tabelname add new_field_id int(5) unsigned default 0 not null auto_increment ,add primary key (new_field_id);

alter table infos add ex tinyint not null default '0′;

alter table t2 drop column c;

alter table t1 change a b integer;
alter table t1 change b b bigint not null;
alter table infos change list list tinyint not null default '0′;

alter table t1 rename t2;

mysql> alter table tablename change depno depno int(5) not null;
mysql> alter table tablename add index 索引名 (字段名1[，字段名2 …]);
mysql> alter table tablename add index emp_name (name);

mysql> alter table tablename add primary key(id);

mysql> alter table tablename add unique emp_name2(cardnumber);

mysql>alter table tablename drop index emp_name;

ALTER TABLE yourtablename
  ADD [CONSTRAINT symbol] FOREIGN KEY [id] (index_col_name, …)
  REFERENCES tbl_name (index_col_name, …)
  [ON DELETE {RESTRICT | CASCADE | SET NULL | NO ACTION}]
  [ON UPDATE {RESTRICT | CASCADE | SET NULL | NO ACTION}]

ALTER TABLE yourtablename DROP FOREIGN KEY fk_symbol;

mysql> SHOW CREATE TABLE ibtest11c\G
*************************** 1. row ***************************
    Table: ibtest11c
Create Table: CREATE TABLE ibtest11c (
 A int(11) NOT NULL auto_increment,
 D int(11) NOT NULL default '0′,
 B varchar(200) NOT NULL default ”,
 C varchar(175) default NULL,
 PRIMARY KEY (A,D,B),
 KEY B (B,C),
 KEY C (C),
 CONSTRAINT 0_38775 FOREIGN KEY (A, D)
REFERENCES ibtest11a (A, D)
ON DELETE CASCADE ON UPDATE CASCADE,
 CONSTRAINT 0_38776 FOREIGN KEY (B, C)
REFERENCES ibtest11a (B, C)
ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=INNODB CHARSET=latin1
1 row in set (0.01 sec)
 
mysql> ALTER TABLE ibtest11c DROP FOREIGN KEY 0_38775;

SHOW CREATE TABLE tbl_name;

SHOW TABLE STATUS FROM db_name LIKE ‘tbl_name';

mysql> SET FOREIGN_KEY_CHECKS = 0;
mysql> SOURCE dump_file_name;
mysql> SET FOREIGN_KEY_CHECKS = 1;