https://blog.csdn.net/heqiyu34/article/details/6238278
查主键:
select * from user_constraints where constraint_name like '%xxx%';
查看主键对应的具体字段:
select * from user_cons_columns where table_name like '%xxx%' and constraint_name like '%xxx%';;
查看索引:
select * from user_indexes a,user_ind_columns b where a.index_name=b.index_name and b.table_name like '%xxx%';
drop constraint是没有删除index的。