Thread: Looking for some help with cascading updates...

<br />Here is the question:<br /><br />I have a situation where I need to create triggers to cascade an insert
operationto many tables to maintain foreign key constraints.  <br /><br />So at a high level<br /><br />INSERT INTO
myTable(Name, Address, Zip) VALUES ('Mark', '3 Dingle St.', '01832') <br /><br />myTable has a relation to two other
tables,which contain Zip and Address.  Before I insert into  myTable I want to:<br /><br />Check if '3 Dingle St.'
existsin table Address, if not insert it<br />Check if '01832' exists in table Zip and if not insert it <br /><br />I
wantto generalize this so that for any insert into myTable, I guarantee that if Zip and Address are not populated they
willbe.  My insert into myTable always contains full information required for doing the inserts into the other related
tables.<br /><br />Help?<br /><br />--Mark<br /><br /> 

Mark True <darfoo@gmail.com> schrieb:

> 
> Here is the question:
> 
> I have a situation where I need to create triggers to cascade an insert
> operation to many tables to maintain foreign key constraints. 
> 
> So at a high level
> 
> INSERT INTO myTable (Name, Address, Zip) VALUES ('Mark', '3 Dingle St.',
> '01832')
> 
> myTable has a relation to two other tables, which contain Zip and Address. 
> Before I insert into  myTable I want to:
> 
> Check if '3 Dingle St.' exists in table Address, if not insert it
> Check if '01832' exists in table Zip and if not insert it

For such task i write a function (plpgsql). This obtains all parameters,
do the checks and insert into the other tables and the table with the fk
constraints.


HTH, Andreas
-- 
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect.                              (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly."    (unknow)
Kaufbach, Saxony, Germany, Europe.              N 51.05082°, E 13.56889°

I guess I should have clarified.  I am having trouble figuring out how to construct the IF statement to see if that item exists in the foreign table something like:

count=select count(*) from table;

if count=0 {
insert fkey into myOtherTable
}

Mark True <darfoo@gmail.com> schrieb:

> I guess I should have clarified.  I am having trouble figuring out how to
> construct the IF statement to see if that item exists in the foreign table
> something like:
> 
> count=select count(*) from table;
> 
> if count=0 {
> insert fkey into myOtherTable
> }

a real example:
(table harz_ufpos references harz_uf)


create or replace function gh_insert(text,int,int,text,int,float) returns int as $$
declare c       int;
begin       select into c count(*) from harz_uf where (uf,ab) = ($1,$2);       if c = 0 then               insert into
harz_uf(uf,ab,beschreibung,aktiv) values ($1,$2,$4,'t');       end if;
 
       insert into harz_ufpos (uf,pos,anzahl,rest,flaeche) values ($1,$3,$5,$5,$6);
       return 1;
end;
$$ language 'plpgsql';


HTH, Andreas
-- 
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect.                              (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly."    (unknow)
Kaufbach, Saxony, Germany, Europe.              N 51.05082°, E 13.56889°

Next silly question, how do you get your database to like plpgsql...

I do CREATE LANGUAGE 'plpgsql' and it says it is not defined?

--Mark

Mark True <darfoo@gmail.com> schrieb:

> Next silly question, how do you get your database to like plpgsql...

- createlang on the command line
- create language plpgsql; (in psql)

>
> I do CREATE LANGUAGE 'plpgsql' and it says it is not defined?

Strange...


>
> --Mark
>
>
> On 4/18/06, AAnnddrreeaass KKrreettsscchhmmeerr
<_a_k_r_e_t_s_c_h_m_e_r_@_s_p_a_m_f_e_n_c_e_._n_e_t>wrote: 
>      Mark True <_d_a_r_f_o_o_@_g_m_a_i_l_._c_o_m> schrieb:

Please, without HTML and fullquote...


HTH, Andreas
--
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect.                              (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly."    (unknow)
Kaufbach, Saxony, Germany, Europe.              N 51.05082°, E 13.56889°

"Mark True" <darfoo@gmail.com> writes:
> I do CREATE LANGUAGE 'plpgsql' and it says it is not defined?

Should work (in 8.1 anyway).  Could we see the *exact* command and
error message?
        regards, tom lane