查询 添加/删除 表的主键

SELECT * FROM ALL_IND_COLUMNS WHERE ROWNUM<3;
查询表的主键1：
Select t.*, i.Index_Type
From User_Ind_Columns t, User_Indexes i
Where t.Index_Name = i.Index_Name And t.Table_Name = i.Table_Name 
And t.Table_Name Like '%HSC_SUBS_PRODUCT%';
查询表的主键2:(好)
Select a.Constraint_Name, a.Column_Name
From User_Cons_Columns a, User_Constraints b
Where a.Constraint_Name = b.Constraint_Name And b.Constraint_Type = 'P' 
And a.Table_Name Like '%HSC_SUBS_PRODUCT%';

查找表的唯一性约束（包括名称，构成列）
Select Column_Name
From User_Cons_Columns Cu, User_Constraints Au
Where Cu.Constraint_Name = Au.Constraint_Name And Au.Constraint_Type = 'u' And Au.Table_Name=UPPER('hsc_chg_req');

5、查询表的所有列及其属性
Select t.*, c.Comments
From User_Tab_Columns t, User_Col_Comments c
Where t.Table_Name = c.Table_Name And t.Column_Name = c.Column_Name And t.Table_Name = 要查询的表......

alter table FSHSC.HSC_SUBS_ATTRINFO2001
   add constraint PK_HSC_SUBS_ATTRINFO2001 primary key (SUB_ATTACH_ID);

--alter table GDHSC.HSC_SUBS_ATTRINFO2001
   drop primary key cascade;

--drop table GDHSC.HSC_SUBS_ATTRINFO2001 cascade constraints;

Select a.Constraint_Name, a.Column_Name
From User_Cons_Columns a, User_Constraints b
Where a.Constraint_Name = b.Constraint_Name And b.Constraint_Type = 'P' 
And a.Table_Name Like '%HSC_SUBS_PRODUCT%';