MySQL field modification

mysql alter Sentence usage , add to 、 modify 、 Delete fields, etc

// Primary key 549830479

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

// Add a new column 549830479

   alter table t2 add d timestamp;
alter table infos add ex tinyint not null default '0';

// Delete column 549830479

   alter table t2 drop column c;

// To be ranked high 549830479

   alter table t1 change a b integer;

// Change the type of the column 549830479

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

// rename table 549830479

   alter table t1 rename t2;

Suo Yin 549830479

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

Index with primary key 549830479

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

Index with unique restrictions 549830479

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

Delete an index 549830479

   mysql>alter table tablename drop index emp_name;

Modify table ：549830479

Add fields ：549830479

   mysql> ALTER TABLE table_name ADD field_name field_type;

Modify the original field name and type ：549830479

   mysql> ALTER TABLE table_name CHANGE old_field_name new_field_name field_type;

Delete field ：549830479

   mysql> ALTER TABLE table_name DROP field_name; 


 Link to the original text ：http://www.blogjava.net/Alpha/archive/2007/07/23/131912.html