Re: Misunderstanding with JDBCR4

Thanks again, Scott and one more question - to the program author.
 I've realized that Oracle connection string delivered to me by the
ORacle admin is somehow - longer than 256 bytes.
Can I change the definitions of "url" in JDBC_ConnProp and
JDBC_Connect to something longer - 512, for example?

TIA,
J.A.


On Fri, Dec 16, 2016 at 11:50 PM, Scott Klement <[email protected]> wrote:
> Jevgeni,
>
> RPG always passes a minimal operational descriptor (one where the count of
> parameters is passed.)  Usually, that is only used when an RPG procedure has
> options(*NOPASS) on a parameter.
>
> JDBCR4 currently only uses this feature for null indicators, so you can get
> by with only adding #pragma descriptor to those.  But, if in the future, you
> wish to call any other RPG procedure that uses options(*NOPASS) (potentially
> for other things) you'll want to be sure to add the #pragma there, too.
>
> On a similar note, when RPG has options(*omit), that means that you can pass
> a NULL pointer for that parameter if you wish.   Since the null indicators
> in JDBCR4 use *OMIT (in addition to *NOPASS) if you don't want to use a null
> indicator sometimes, you could pass a NULL pointer for the null indicator
> parameter.
>
> Hope that helps...
>
>
>
>
>
> On 12/16/2016 8:30 AM, Jevgeni Astanovski wrote:
>>
>> In fact I have already solved the problem.
>> A little googling around for "operational descriptor"....
>>
>> I just had to modify my header file and add one row for JDBC_GetCol:
>>
>> #pragma descriptor(void JDBC_GETCOL(void , void, ""))
>>
>> With this RPG understood, that number of parameters is 3 and returned
>> me the correct value of nullInd.
>>
>>
>> Of course also added the same pragma to all other functions that deal
>> wit nullInd - just in case...
>>
>> Thanks,
>>
>> Jevgeni.
>>
>>
>> On Fri, Dec 16, 2016 at 4:04 PM, Ron Unknown <[email protected]>
>> wrote:
>>>
>>> Jevgeni,
>>>
>>> I am not sure, it has been so long since I have messed with 400s,  but is
>>> the pointer given an initial value before calling the program? something
>>> like:
>>>
>>> Dcl Y-Ptr *     init(*null) or based(*null)
>>>
>>> not sure of the syntax any more, before it is called so that the sytem
>>> knows it is a pointer?
>>>
>>>
>>> ________________________________
>>> From: C400-L <c400-l-bounces-Zwy7GipZuJhWk0Htik3J/[email protected]> on behalf of Jevgeni
>>> Astanovski <[email protected]>
>>> Sent: Friday, December 16, 2016 2:55 AM
>>> To: Bare Metal Programming IBM i (AS/400 and iSeries)
>>> Subject: [C400-L] Misunderstanding with JDBCR4
>>>
>>> Hi, collegues
>>> Having a challenge of accessing external database from my ILE/C
>>> program, looked at Scott Klement JDBCR4.
>>> As I do not write RPG, had to spend some time porting library header
>>> from RPG to C. Not a big job.
>>> Generally works fine.
>>> However when I tried to see how JDBC_GetCol returns NullInd in case
>>> field is empty, ran into a problem.
>>>
>>> JDBC_GetCol is prototyped so:
>>>
>>> VAR32767 JDBC_GETCOL(RESHANDLE *, int, char *) ;
>>> VAR32767 and RESHANDLE are my defined types and they work fine.
>>>
>>> I call this function in my program:
>>>
>>> RESHANDLE rs ;
>>> char NullInd ;
>>> VAR32767 Field ;
>>>
>>> Field = JDBC_GETCOL(&rs, 48, &NullInd) ;
>>>
>>> It returns field value fine, however NullInd is always unchanged -
>>> field is empty or not.
>>> Run in debugger mode to see what Scott's program does.
>>> His function looks so:
>>>
>>> P JDBC_GetCol B export
>>> D JDBC_GetCol PI 32767A varying
>>> D rs like(ResultSet)
>>> D col 10I 0 value
>>> D nullInd 1N options(*nopass:*omit)
>>> D result s 32767A varying
>>> D str s like(jstring)
>>> D null s 1N inz(*OFF)
>>>
>>> /free
>>>
>>> jdbc_begin_object_group(5);
>>>
>>> monitor;
>>> str = getColString(rs: col);
>>> if (str = *NULL);
>>>   result = '';
>>>   null = *ON;
>>> else;
>>>   result = r(str);
>>> endif;
>>> on-error;
>>> null = *ON;
>>> result = '';
>>> endmon;
>>> jdbc_end_object_group();
>>> if (%parms >= 3 and %addr(nullInd)<>*NULL);
>>>   nullInd = Null;
>>> endif;
>>>
>>> return result;
>>>
>>> /end-free
>>>
>>> Sorry for the formatting...
>>>
>>> What my debugging show is that Null variable has a proper value, but
>>> is never assigned to nullInd.
>>> I added NumParms variable and assigned value of %parms to it.
>>> From that I saw that NumParms is -1, however all 3 parameters are passed.
>>>
>>> Had a look at the manual for %parms.
>>> It says the following:
>>> "The value returned by %PARMS will be -1 if the system can determine
>>> that the operational
>>> descriptor was not passed, but in some cases when the system cannot
>>> detect this,
>>> the value returned by %PARMS may be an incorrect value that is zero or
>>> greater."
>>>
>>> Is there anything I can do about it?
>>>
>>> Any advise will be highly appreciated...
>>>
>>> Jevgeni.
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