create database defaultStudy;
use defaultStudy;
create table paly (id int comment '编号', name varchar(64)comment'玩家命名',reflag varchar(1024) default ''comment "签名");
show create table paly ;
desc paly;
insert into paly values(1,'xxx',"");
select * from paly ;
alter table paly add constraint Paly_id primary key(id);
show index from paly;
show keys from paly;
alter table paly add constraint Paly_Name unique(name);
create table reCharacter (id int ,name varchar(64) , palyID INT);
alter table recharacter add constraint Palyid foreign key (palyID) REFERENCES paly(id);
show keys from reCharacter;
alter table paly drop primary key;
alter table paly drop key Paly_Name;
alter table recharacter drop Foreign Key Palyid;
show index from recharacter;
alter table paly modify id int auto_increment;
alter table paly modify id int ;
alter table paly modify ID int default 0;
alter table paly modify id int ;
alter table paly modify name varchar(64) not null;
alter table paly modify name varchar(64);
ALTER table paly modify reflag VARCHAR(1024) default ' ';
ALTER table paly modify reflag VARCHAR(1024) ;