[Announce] libzdb 2.1

[Martin Pala]

Jan-Henrik Haukeland wrote:
>> - I can't use Connection_PreparedStatement on a postgresql  
>> connection until I've
>> issued a Connection_executeQuery. Doing so segfaults in libzdb. I've  
>> reported
>> this one already, and I can easily work around this.
> 
> Its on my TODO list and I hope to have it moved over to Martin's TODO  
> list :)

Hi,

the problem should be fixed ... postgresql returned PGRES_EMPTY_QUERY 
for PQprepare() whereas libzdb expected PGRES_COMMAND_OK or 
PGRES_TUPLES_OK. I have checked the postgresql code and it seems that 
PGRES_EMPTY_QUERY is not error in this context - the prepared statement 
is processed fine. I have modified the code to check for result (C->res) 
of PQprepare() and accept the PGRES_EMPTY_QUERY.


Note that to prevent the uncaught exception like this:

--8<--
Uncaught exception SQLException raised in Connection_prepareStatement at
src/db/Connection.c:294
--8<--

you should modify your code using TRY-CATCH-END_TRY this way:

--8<--
         TRY
         {
                 PreparedStatement_T p = 
Connection_prepareStatement(con, "SELECT * FROM dbmail_users WHERE 
userid=?;");
                 if (! p)
                         printf("[%s]", Connection_getLastError(con));
                 assert(p);
         }
         CATCH(SQLException)
         {
                 printf("\tResult: prepare statement failed -- %s\n", 
Connection_getLastError(con));
         }
         END_TRY;
--8<--

This way you will get the the error message printed out and the program 
won't crash.


The patch is in the cvs and attachment as well.

Cheers,
Martin








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