SQLite Problem in 4.5

Peter Haworth pete at mollysrevenge.com
Tue Nov 16 16:15:39 EST 2010


Hi Bob,
I forgot one important fact in deciding whether this is a bug or not -  
the SELECT statement worked fine in 4.0 with exactly the same data,  
NULLs and all.  So something got changed in 4.5 that caused this to  
stop working.  I will enter this issue into the QCC this afternoon.

Pete Haworth

On Nov 15, 2010, at 3:49 PM, Bob Sneidar wrote:

> I don't think it is a bug. Since the NULL's are embedded into the  
> SQL result, when LiveCode sees them it thinks it's an EOF of some  
> kind (help me out Jacque wasn't this discussed in an earlier thread)?
>
> If you had queried each column as is, then concatenated them in  
> LiveCode, I think you would have gotten all the data. I think the  
> query IS working, but the NULL in the cursor is being interpreted by  
> LiveCode as an end of data marker. Should it be? I will leave that  
> to bigger minds than mine. I think this behavior is a backwards  
> compatibility issue with Metacard stacks or something. I vaguely  
> remember this being discussed a few months ago. But I could be  
> wrong. Well... not really. ;-)
>
> Bob
>
>
> On Nov 15, 2010, at 3:12 PM, Peter Haworth wrote:
>
>> Avoiding NULLs is always good I think.  But since SQLite itself  
>> works fine with them and LiveCode doesn't, this feels like a bug to  
>> me.  Should I enter it at the QCC?
>>
>> Pete Haworth
>>
>> On Nov 15, 2010, at 3:06 PM, Bob Sneidar wrote:
>>
>>> Ah hah! Nice catch. I thought Rev was supposed to interpret NULL  
>>> as empty string, but with the concatenation, I suppose the NULL's  
>>> would be embedded in the returned pseudo column (probably not the  
>>> right word for it). That is a nice little gotcha there for anyone  
>>> running this kind of query. Moral to story: avoid NULL values in  
>>> LiveCode SQL databases?
>>>
>>> Bob
>>>
>>>
>>> On Nov 15, 2010, at 2:58 PM, Peter Haworth wrote:
>>>
>>>> Thanks Bob.  I think the problem may have something to do with  
>>>> NULL values in some of the columns coming back from the SELECT.   
>>>> When I fixed them, the SELECT worked fine in LiveCode.  The  
>>>> Firefox plugin was one of the utilities I used to check this out  
>>>> and it returned all the data correctly, even when there were  
>>>> NULLs in the columns.
>>>>
>>>> Pete Haworth
>>>
>>> _______________________________________________
>>> use-revolution mailing list
>>> use-revolution at lists.runrev.com
>>> Please visit this url to subscribe, unsubscribe and manage your  
>>> subscription preferences:
>>> http://lists.runrev.com/mailman/listinfo/use-revolution
>>>
>>
>> _______________________________________________
>> use-revolution mailing list
>> use-revolution at lists.runrev.com
>> Please visit this url to subscribe, unsubscribe and manage your  
>> subscription preferences:
>> http://lists.runrev.com/mailman/listinfo/use-revolution
>
> _______________________________________________
> use-revolution mailing list
> use-revolution at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your  
> subscription preferences:
> http://lists.runrev.com/mailman/listinfo/use-revolution
>




More information about the Use-livecode mailing list