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How do you evaluate for NULL in ADO

Posted on 2002-07-01
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Last Modified: 2010-04-01
I am trying to retrieve the value of a field that could be NULL.  I do this by using the following call:

strcpy(string, (LPCSTR)(_bstr_t)pFields->GetItem(vtIndex)->Value);

My database allows fields to be NULL.  Therefore, unless I want to keep receiving an exception error, I need to check the value for NULL.  Problem is, I'm not sure how to do that.  

Can someone help?!?
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Question by:kingservant
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6 Comments
 
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Expert Comment

by:Chizl
ID: 7123275
Looks like your doing a RecordSet loop.  I would suggest you try GetRows(-1) to get your data returned into a _variant_t array, then close your recordset.   Then your eval will be much simpler and your process time will be much faster.

I have an example of this up on:
http://www.chizl.com/dev/c++/

Let me know if you have any questions about it.
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Expert Comment

by:Chizl
ID: 7123279
BTW.. About the NULL, try catch() is the solution, but still suggest using GetRows(-1).   The -1 is for all records.
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Chizl earned 350 total points
ID: 7123282
hehe.. Post again..  If you go the way I suggest you would use this:

http://support.microsoft.com/default.aspx?scid=kb;EN-US;q229088
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Author Comment

by:kingservant
ID: 7123463
Out of all the people who have responded to me on this forum, you have got to be the best!  Thanks for your response, complete with code examples and links, I love it.  I'll grade your answer tomorrow after I get to work.  BTW, do you have any other suggestions I could make to my code to make it more efficient?
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Author Comment

by:kingservant
ID: 7124508
Thanks for you response.  You're the best!
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Author Comment

by:kingservant
ID: 7124743
Thanks for you response.  You're the best!
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