Where is the problem ?

Hi!

I am a beginning postgres user and having a more or less free weekend I
decided to do a test application using sql. Well all is not so great
because when I run "select logz('abc','mswindows',2)\g followed by a
select * from ipl_use\g I get a core dump :((( Does anybody know whats
wrong ? Also How do you use the transactions (begin/end) correctly ?
Also 2: Is there a way to get Insert to insert only when a condition is
met such as when there is no such user ?

BTW: I am running postgres 6.2.1 on a RedHat 5.* system.

Best regards,

/apj

-----------------------------[CUT]------------------------------------

CREATE TABLE ipl_ads (
ln int4,
ad varchar(60),
owner varchar(60),
fromwhen date,
counter int4
);

CREATE TABLE ipl_use (
ln int4,
user varchar(128),
prog varchar(128),
ad int4,
wdate date,
wtime time
);

CREATE SEQUENCE ad_ln;
CREATE SEQUENCE use_ln;

create table ad_num (f1 int4);
insert into ad_num values (1);

create table licz (f2 int4);
insert into licz values (1);

create function licznik() returns int4 as
'begin;
update licz set f2 = f2 + 1;
end;
select f2 from licz; '
language 'sql';

create function which_ad(int4) returns int4 as
'begin;
update ad_num set f1 = f1 + 1 where ad_num.f1 <= $1;
update ad_num set f1 = 1 where ad_num.f1 > $1;
update ipl_ads set counter = counter + 1 where ipl_ads.ln = ad_num.f1;
end;
select ln from ipl_ads where ipl_ads.ln = ad_num.f1; '
language 'sql';

create function logz(varchar, varchar, int4) returns int4 as
'insert into ipl_use values (licznik(), $1, $2, $3, current_date, current_time);
select ln from ipl_use where ipl_use.ln = licz.f2; '
language 'sql';

update licz set f2 = 2;