How to add a Primary Key on a Oracle view? [duplicate]

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Possible Duplicate:

adding primary key to sql view

I'm working开发者_运维百科 with a software that requires a primary key in a Oracle view. There is possible to add a Primary key in a Oracle view? If yes, how? I can't google information about this.

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The SQL standard unfortunately only permits UNIQUE and PRIMARY KEY constraints on base tables, not views. Oracle permits unique indexes on materialized views but not on views generally.

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The only thing that comes in my mind is using a materialized view and then create a unique index on it:

drop materialized view tq84_mat_view;
drop table tq84_table;
create table tq84_table (
  a number,
  b number
);

create materialized view tq84_mat_view 
refresh on commit as
select 
  a,
  sum(b) sum_b
from 
  tq84_table
group by
  a;

create unique index tq84_mat_view_uix on tq84_mat_view (sum_b);

insert into tq84_table values (1, 1);
insert into tq84_table values (2, 2);
insert into tq84_table values (1, 4);

commit;

insert into tq84_table values (2, 3);

commit;
--> ORA-12008: error in materialized view refresh path
--> ORA-00001: unique constraint (SPEZMDBA.TQ84_MAT_VIEW_UIX) violated

While this might be useful, it must be kept in mind that the materialized view, as opposed to a "normal" view occupies space in a tablespace. And of course, the index needs space, too.

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This is the way by which you can add a primary key in your view.

CREATE OR REPLACE FORCE VIEW VU_NAME
        (
          PRIMARY_KEY, NAME_ID, ADDRESS_ID
         )
        AS 
        SELECT DISTINCT ROWNUM AS PRIMARY_KEY,
            NAME.ID UNIT_ID,
            ADDRESS_ID
        from table1;