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From: veem v <veema0000@gmail.com>
Date: Wed, 12 Jun 2024 00:50:27 +0530
Message-ID: <CAB+=1TWb2ASHes8ynVcWs9DAuOgKsY-m-EAJfNwqE0=F=03Uug@mail.gmail.com>
Subject: Re: Does trigger only accept functions?
To: depesz@depesz.com
Cc: pgsql-general <pgsql-general@lists.postgresql.org>
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On Wed, 12 Jun 2024 at 00:26, hubert depesz lubaczewski <depesz@depesz.com>
wrote:

>
>
> No, I meant building dynamic queries and then EXECUTE-ing, like docs
> show:
>
> https://www.postgresql.org/docs/current/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN
>
> Best regards,
>
> depesz
>
>
My apology, if interpreting it wrong way. It doesn't make much difference
though, but do you mean something like below?

CREATE OR REPLACE FUNCTION log_deletes()
RETURNS TRIGGER AS $$
DECLARE
    audit_table_name TEXT;
    audit_query TEXT;
BEGIN
    IF TG_TABLE_NAME = 'source_table1' THEN
        audit_table_name := 'delete_audit1';
        audit_query := 'INSERT INTO ' || audit_table_name || ' (record_id,
delete_timestamp, col1, col2, col3) VALUES ( $2, $3, $4)';
        EXECUTE audit_query USING OLD.id, OLD.col1, OLD.col2, OLD.col3;
    ELSIF TG_TABLE_NAME = 'source_table2' THEN
        audit_table_name := 'delete_audit2';
        audit_query := 'INSERT INTO ' || audit_table_name || ' ( col4,
col5, col6) VALUES ( $2, $3, $4)';
        EXECUTE audit_query USING OLD.id, OLD.col4, OLD.col5, OLD.col6;

    ELSE
        RAISE EXCEPTION 'Audit table not defined for %', TG_TABLE_NAME;
    END IF;

    RETURN OLD;
END;
$$ LANGUAGE plpgsql;

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><br><div class=3D"gmail_quote">=
<div dir=3D"ltr" class=3D"gmail_attr">On Wed, 12 Jun 2024 at 00:26, hubert =
depesz lubaczewski &lt;<a href=3D"mailto:depesz@depesz.com">depesz@depesz.c=
om</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"margi=
n:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex=
"><br>
<br>
No, I meant building dynamic queries and then EXECUTE-ing, like docs<br>
show:<br>
<a href=3D"https://www.postgresql.org/docs/current/plpgsql-statements.html#=
PLPGSQL-STATEMENTS-EXECUTING-DYN" rel=3D"noreferrer" target=3D"_blank">http=
s://www.postgresql.org/docs/current/plpgsql-statements.html#PLPGSQL-STATEME=
NTS-EXECUTING-DYN</a><br>
<br>
Best regards,<br>
<br>
depesz<br>
<br></blockquote><div><br></div><div>My apology, if interpreting it wrong w=
ay. It doesn&#39;t=C2=A0make much difference though, but do you mean someth=
ing like below?</div><div><br></div><font face=3D"monospace">CREATE OR REPL=
ACE FUNCTION log_deletes()<br>RETURNS TRIGGER AS $$<br>DECLARE<br>=C2=A0 =
=C2=A0 audit_table_name TEXT;<br>=C2=A0 =C2=A0 audit_query TEXT;<br>BEGIN<b=
r>=C2=A0 =C2=A0 IF TG_TABLE_NAME =3D &#39;source_table1&#39; THEN<br>=C2=A0=
 =C2=A0 =C2=A0 =C2=A0 audit_table_name :=3D &#39;delete_audit1&#39;;<br>=C2=
=A0 =C2=A0 =C2=A0 =C2=A0 audit_query :=3D &#39;INSERT INTO &#39; || audit_t=
able_name || &#39; (record_id, delete_timestamp, col1, col2, col3) VALUES (=
 $2, $3, $4)&#39;;<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 EXECUTE audit_query USING=
 OLD.id, OLD.col1, OLD.col2, OLD.col3;<br>=C2=A0 =C2=A0 ELSIF TG_TABLE_NAME=
 =3D &#39;source_table2&#39; THEN<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 audit_tabl=
e_name :=3D &#39;delete_audit2&#39;;<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 audit_q=
uery :=3D &#39;INSERT INTO &#39; || audit_table_name || &#39; ( col4, col5,=
 col6) VALUES ( $2, $3, $4)&#39;;<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 EXECUTE au=
dit_query USING OLD.id, OLD.col4, OLD.col5, OLD.col6;<br>=C2=A0 =C2=A0 <br>=
=C2=A0 =C2=A0 ELSE<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 RAISE EXCEPTION &#39;Audi=
t table not defined for %&#39;, TG_TABLE_NAME;<br>=C2=A0 =C2=A0 END IF;<br>=
<br>=C2=A0 =C2=A0 RETURN OLD;<br>END;<br></font><div><font face=3D"monospac=
e">$$ LANGUAGE plpgsql;</font>=C2=A0</div></div></div>

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