Re: ON DELETE CASCADE

Here is a function that I use to list fk(triggers) on a table.  Execute the
function to get the trigger name and then - drop trigger "trigger_name" on
table_name;

hth

-- Version 1.0, June 2002
-- Marie G. Tuite

-- Function lists FK by table.
-- To execute:
-- begin;select fn_list_fk('table_name');
-- fetch all from "<cursor_name>"; end;

create or replace function fn_list_fk(name)   returns refcursor as
'
declare   table_in alias for $1;   rc refcursor;
begin   open rc for       select tgname as trigger_name_sys              ,tgconstrname  as trigger_name_given
  ,b.relname as table_name              ,tgisconstraint as ri              ,c.relname as parent_table           from
pg_triggera,                pg_class b,                pg_class c           where a.tgrelid=b.oid and
b.relname=table_in          and tgconstrrelid = c.oid;
 
   return rc;
end;
'
language 'plpgsql'

;

> -----Original Message-----
> From: pgsql-sql-owner@postgresql.org
> [mailto:pgsql-sql-owner@postgresql.org]On Behalf Of Tim Perdue
> Sent: Thursday, December 12, 2002 11:01 AM
> To: pgsql-sql@postgresql.org
> Subject: [SQL] ON DELETE CASCADE
>
>
> I'm trying to comb through my database and add ON DELETE CASCADE to a
> number of tables where I already have fkeys in place, but I'm having a
> hard time.
>
> ALTER TABLE project_task DROP CONSTRAINT
> "project_task_group_project_id_f" RESTRICT;
>
> ERROR:  ALTER TABLE / DROP CONSTRAINT: project_task_group_project_id_f
> does not exist
>
> ALTER TABLE project_task
>     ADD CONSTRAINT projecttask_groupprojectid_fk
>     FOREIGN KEY (group_project_id)
>     REFERENCES project_group_list(group_project_id) ON DELETE CASCADE;
> NOTICE:  ALTER TABLE will create implicit trigger(s) for FOREIGN KEY
> check(s)
> ALTER
>
> That command works, but now I think I have 2x as many triggers as I
> want. How do I get rid of the original triggers?
>
>
> alexandria=# \d project_task
>                                      Table "project_task"
>        Column      |       Type       |         Modifiers
> ------------------+------------------+-----------------------
>   project_task_id  | integer          | not null default
> nextval('project_task_pk_seq'::text)
>   group_project_id | integer          | not null default '0'
>   summary          | text             | not null default ''
>   details          | text             | not null default ''
>   percent_complete | integer          | not null default '0'
>   priority         | integer          | not null default '0'
>   hours            | double precision | not null default '0.00'
>   start_date       | integer          | not null default '0'
>   end_date         | integer          | not null default '0'
>   created_by       | integer          | not null default '0'
>   status_id        | integer          | not null default '0'
> Indexes: projecttask_projid_status
> Primary key: project_task_pkey
> Triggers: RI_ConstraintTrigger_51030049,
>            RI_ConstraintTrigger_51030047,
>            RI_ConstraintTrigger_4305858,
>            RI_ConstraintTrigger_4305852,
>            RI_ConstraintTrigger_4305846
>
> After adding the new foreign key:
>
> Triggers: RI_ConstraintTrigger_51364957, ***new
>            RI_ConstraintTrigger_51030049,
>            RI_ConstraintTrigger_51030047,
>            RI_ConstraintTrigger_4305858,
>            RI_ConstraintTrigger_4305852,
>            RI_ConstraintTrigger_4305846
>
>
>
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