--1. 删除原主键
alter table uinfor
drop constraint PK_uinfor
--2. 删除字段
alter table uinfor
drop column u_id
--3. 添加字段
alter table uinfor
add u_note varchar(1) NULL
--4. 修改字段
ALTER TABLE uinfor
ALTER COLUMN u_key VARCHAR(18) NOT NULL
--5. 添加新主键
alter table uinfor
add primary key(u_key ,u_name )
alter table uinfor
drop constraint PK_uinfor
--2. 删除字段
alter table uinfor
drop column u_id
--3. 添加字段
alter table uinfor
add u_note varchar(1) NULL
--4. 修改字段
ALTER TABLE uinfor
ALTER COLUMN u_key VARCHAR(18) NOT NULL
--5. 添加新主键
alter table uinfor
add primary key(u_key ,u_name )
Being a devil is the same as being a human. We should be kind. If we are kind, we are not a devil, we are a hybrid.