Re: Kind of error-handler in a pgsql function - Mailing list pgsql-sql

There is _no error handling_ in plpgsql

You can find documentation at:
http://www.postgresql.org/idocs/index.php?plpgsql.html

On Thu, 5 Jul 2001, [iso-8859-1] DI Hasen�hrl wrote:

> Thank you for your example. I understand, in order to avoid inserting
> *duplicate keys*, first I try to update, when it fails make an insert.
> But other errors may occur, is there a possibility to distinguish
> between errors by an error-number. Please can you tell me, where I can
> find system functions, variables like *diagnostics, row_count, found,
> and so on.....* I studied the docu in
> http://www.ca.postgresql.org/devel-corner/docs/postgres/programmer.html,
> but I didn't find
> 
> Many thanks in advance
> Irina
> 
>   You must do it the other way around: 
> 
>   First, try update, then see how many records were updated, if there were 0
>   records updated, then do the insert.
> 
>   Currently, plpgsql lacks decent exception handling. 
> 
>   Sample code:
> 
>   create function ...
>   ...
>   declare rec_affected int;
>   begin
>     update ... 
>     get diagnostics rec_affected = ROW_COUNT;
>     if rec_affected = 0 then  
>       insert ...
>     end if;
>   end;
> 
>   On Wed, 4 Jul 2001, [iso-8859-1] DI Hasen�hrl wrote:
> 
>   > Hi,
>   > 
>   > When I write in psql:
>   > testdb=# update table1 set tableattribute='any' where table_nr=1;
>   >     if a tuple exists, I get this message 
>   > testdb=# update 1
>   >     if no tuple with table_nr=1 exists, I get this message
>   > testdb=# update 0
>   >     
>   > 
>   > Is there a possibility to make a difference in a pgsql function like this:
>   > create function updTable(text,integer) returns int AS
>   > 'DECLARE
>   >    msg ALIAS FOR $1;
>   >    nr    ALIAS FOR $2;
>   >  BEGIN
>   >      update table1 set tableattribute=msg where table_nr=nr;
>   >      --pseudocode
>   >        if update = 0 then
>   >          return 0;
>   >        else
>   >          return 1;
>   >        end if;
>   >    END;
>   > 'language 'plpgsql';
>   > 
>   > or for a function, which inserts data:
>   > create function insTable(text,integer) returns int AS
>   > 'DECLARE
>   >    msg ALIAS FOR $1;
>   >    nr    ALIAS FOR $2;
>   >  BEGIN
>   >      insert into table1 values (nr,msg);
>   >      --pseudocode
>   >        if error= cannot insert duplicate key.....then
>   >          return 0;
>   >        else
>   >          return 1;
>   >        end if;
>   >    END;
>   > 'language 'plpgsql';
>   > 
>   > I want to know the result of an insert or update, because I call these functions from an Access form and the next
stepsof the program depend on these results.
 
>   > 
>   > I hope, someone can help me, because I didn't find anything in the docu or mailing list.
>   > Thanks in advance
>   > Irina
>   > 
>   > E-Mail: i.hasenoehrl@aon.at
>   > 
> 
> 
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