Re: Modify Primary Key

  • From: "Norman Dunbar" <norman.dunbar@xxxxxxxxxxxxxxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>, <manoj.gurnani@xxxxxxxxxxxxx>
  • Date: Fri, 14 Oct 2005 13:35:26 +0100

>>> <manoj.gurnani@xxxxxxxxxxxxx> 10/14/05 10:13am >>>

         What are different steps to be followed in modifying a
key(PK1) to exclude last primary key column from a list of primary key
assuming referential integrity  constraints exists on primary key in
give necesary sql syntax to perform the tasks .


Hi Manoj,

you'd need to drop the foreign key constraints from *all* the child
tables whihc reference the primary key you wish to change, then drop the
primary key constraint from the table in question. Once you've done
that, rebuild the primary key and then the foreign key's again.

Something like :

alter table child_1 drop constraint fk_1;
alter table child_2 drop constraint fk_2;
alter table child_3 drop constraint fk_3;
alter table parent drop constraint pk_1;

alter table parent add constraint pk_1 primary key (a,b,c);

alter table child_1 add constraint fk_1 foreign key (x,y,z) references
parent (a,b,c);

and so on.


Norman Dunbar.
Contract Oracle DBA.
Rivers House, Leeds.

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