删除primary key

@H_502_4@alter table tablename drop constraint tablename_pkey;

添加primary key

@H_502_4@alter table tablename add primary key(colname);

添加/删除非空约束

@H_502_4@alter table tablename alter COLUMN colname set/drop not null;

添加列

@H_502_4@alter table tablename ADD colname datatype;

删除列

@H_502_4@alter table tablename drop colname

更改列数据类型

@H_502_4@alter table tablename alter colname TYPE datatype;

更改表名

@H_502_4@alter table tablename RENAME TO newtablename