LOGOUT/COMMIT usage

[nenad cikic]

Since LOGOUT now works I have tried it. First excuse my limit knowledge on the matter since, unfortunately, I do not use it in our main application. Anyway I have found that LOGOUT/COMMIT essentially works. I wanted just to point to 2 or 3 things I have discovered:

This is my code:
     LOGOUT(10,tecajna_lista,tecajevi)
     if errorcode()
        message('Greška pri pokretanju transakcije!')
        ROLLBACK
        return retVal
     end

     !dodaj domaću valutu
     clear(tecajevi)
     tec:valuta_brojcano=dom_valuta
     tec:kupovni_tecaj=1
     tec:prodajni_tecaj=1
     tec:valuta_slovcano=val:oznaka
     tec:tl_broj_tecajne_liste=tl:broj_tecajne_liste
     tec:tl_datum_tecajne_liste=tl:datum_tecajne_liste
     tec:vmt_vrsta_tecaja='RED'
     tec:paritet=val:paritet
     tec:blokada='N'
     add(tecajevi)
     if errorcode()
        message('Greška pri automatskom dodavanju domaće valute na tečajnu listu!')
        ROLLBACK
        return retVal
     end

     tl:indikator='2'
     put(tecajna_lista)
     if errorcode()
        message('Greška pri ažuriranju statusa tečajne liste!')
        ROLLBACK
        return retVal
     end

     COMMIT
     if not errorcode()
        retVal=true
     end

1. This is just a question: Is it correct to use ROLLBACK if LOGOUT fails?
2.If i comment the block if errorcode() after add(tecajevi), so no ROLLBACK is executed, I got error on put(tecajna_lista)
This seems strange to me. I would expect to add(tecajevi) silently fail and put(tecajna_lista) and COMMIT succedd.
3.How can I check if COMMIT succedded? It seems to me that if I put blindly
ROLLBACK
COMMIT

the file tecajna_lista is correctly not updated but COMMIT stil returns true

Thanks
Nenad

[Andrew Barnham]

1.  Calling rollback on failed logout is fine.  Doesn't really matter; not necessary. But it doesn't cause harm
2. reason why PUT is failing is connected to how postgres works.  If in between a logout/commit, any error occurs, then no operation to the DB will succeed until you rollback.  There is a way to work around this behaviour if required, using save points.  use {prop:sql} to issue commands to postgres. See postgres documentation on savepoints.
3.  rollback followed by commit means : rollback all changes. The commit then says commit all changes, but since the rollback there are no changes to commit so nothing happens.  Always issue COMMIT() and then check ERRORCODE() afterwards.

[nenad cikic]

OK, then it is all OK.
Super
Nenad

[nenad cikic]

I have noticed that LOGUT/COMMIt works OK even if I have not added all files to LOGOUT statement.
Is tis OK or should I add all files anway to LOGOUT statement?
Thanks

[Andrew Barnham]

You don't need to add any files. LOGOUT applies universally.

I would expect that original clarion works this way too; has to do with the way SQL does transaction frames.  You could in theory make it so logout does pay attention to list of tables (by maintaining multiple database links, one for operations on tables currently in logout list and one for all the others), but it is alot of work and result is code that less robust. 

I cannot think of a legitimate use for wanting to provisionally include some tables in list but not others. If one does indeed exist can take another look at this.