Help with Oracle Query

Question

I want to delete all the records where field name class="10010" from Table A and AentryId = BentryId from Table B.

if i delete the entryId 12 which matches className=10010 from Table A and the same time that same id should delete from Table B also.

Table A:

AentryId  className     
12      10010
13      10011
14      10010
15      10011

Table B:

BentryId  name   
12         xyz
13         abc
14         aaa

Answer 1

Following may be final query you are looking for

delete form TableA where   class="10010" and AentryId in ( select BentryId from tableB)

Cascade delete is one of the option that allow you to delete data from child and form primary table

otherwise you can write query like below

   declare @T table (id int)
   insert into @T  
      select AentryId form TableA where   class="10010" and AentryId in ( select BentryId from tableB)

  delete form TableA where  AentryId in ( select id from @T)
  delete form TableB where  BentryId in ( select id from @T)

Answer 2

The easiest way to do this is through a foreign key defined with CASCADE DELETE:

alter table B 
  add constraint b_a_fk foreign key (BentryId)
  references A (AentryId)
  on delete cascade
/

If you delete a row from A all its dependent records in B are automatically deleted.

Of course, enforcing a foreign key means that you cannot create any rows in B with a BentryId which does not reference a pre-existing AentryId in A. This is normally a desirable thing but not every data model enforces relational integrity.

edit

Dropping the constraint really couldn't be simpler...

alter table B 
  drop constraint b_a_fk 
/