Re: Learning Plpgsql ?? - Mailing list pgsql-novice

On Thu, 2003-01-23 at 14:18, Jonathon Batson wrote:
> Hi
> Newbie to Plpgsql and Postgres.
> I am porting dbs from Access97 to postgres, tables and data comes across
> fine but the autonumber(sequences) do not
> get updated, so I need to do this manually using > SELECT
> setval(sequence_name,value);
> OK , this is no problem, BUT, I have 90 tables in the db, and around 70
> clients to port to postgres.
> So a function to do this is needed.
>
> The direction took so far is to create a  table, seq_table consisting of
>  all the sequences information in the db as follows:
>
>     sequence_name                    table_name            pk_column
> -----------------------------------------------------------------
> customer_number_seq                customer               c_number
> purchase_job_number_seq         purchase                job_number
> etc
>
> Then a function that in psuedo code is something like this
> for each row in seq_table
>     get max(pk_column) from table_name
>     set sequence_name to max
> endfor
>
> So my function is:
>
> -- Function: update_seq()
> CREATE or REPLACE FUNCTION update_seq() RETURNS text AS '
>   DECLARE
>      row RECORD;
>      maxid INTEGER;
>
>   BEGIN
>      -- select sequence information [ sequence_name, table_name, pk_column]
>     FOR row IN SELECT * FROM seq_table LOOP
>
>        --  get the maxid for row.table_name on row.pkcolumn
>        SELECT max(row.pk_column) INTO maxid FROM row.table_name;
>
>        -- then set the sequence value
>        SELECT setval(row.sequence_name,maxid);
>
>     END LOOP;
>
>     RETURN ''done'';
>   END;
> '  LANGUAGE 'plpgsql';


I think you will need to build the queries as text and use EXECUTE to
EXECUTE them:

DECLARE
  dqry TEXT;

...

  dqry := ''SELECT setval('''' || row.sequence_name || '''', '' || maxid
|| '');'';
  EXECUTE dqry;


Section 19.5.4 of the docs.

Cheers,
                    Andrew.

>
> The function fails at the line select into line
> SELECT max(row.pk_column) INTO maxid FROM row.table_name;
> with the following error........something to do with the second var
> row.table_name I think.
>
> swimdb=# SELECT update_seq();
> NOTICE:  Error occurred while executing PL/pgSQL function update_seq
> NOTICE:  line 14 at select into variables
> ERROR:  parser: parse error at or near "$2"
>
> Any ideas would be gratefully accepted...
> Also a direction on some more detailed PL/pgSQL documentation
> Have looked a Postgres Interactive Docs..not so helpfull
>
> Thanks
> Jonathon
>
>
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