Hello!
I have been searching this forum, and also the references on the main qodbc website, and though there are many useful things, I still feel like I am missing something.  I solved a few problems, including finding the soloution to the following post made by another member:

....Appending, updating and retrieving data to/from the QuickBooks CUSTOMER table using standard Access queries works just fine, as long as I observe the restrictions defined by the REQUIRED_ON_INSERT, INSERTABLE, and UPDATEABLE rules for the respective fields.....

He talks about observing the restrictions defined on fields.  I've looked through all the layouts and schema available, and I'm not sure where he referenced those restrictions.  Also, a lot seems to involve a "FQSaveToCache" field, that I cannot find described specifically. 

I am not sure if I am missing some fundamental knowledge base that I should know already, or if I have missed a reference tool somewhere.  I see the potential for my application incorporating QODBC, and I am excited.  I am piecing together the puzzle based on the snipets around the forum.   The intro manual started me off well, but had no helpful details.  The snipets show the potential.  Is there an overview somewhere that could bridge the gap?  Thanks for your help!

Ok, please see:
Where are the schema rules for using QODBC? How do I use sp_columns? 
How can I create multiple lines in the Invoice, Purchase, Journal and other tables? 
How do I create a new Customer, invoice them and mark the invoice as paid? 
How do I add a Inventory Item using QODBC? 
How do I insert data into ItemNonInventory? 
How do I insert data into ItemService?  

Thank you Tom!  The first two links were extremely useful :)  The subsequent links were also good, but I had found them already. 

I could not find the link that explains the FQSavetoCache. I suppose it may be because that term is not in the Topic title.  (One would have thought the search might have found it anyways because of the body.)  Also seems I didn't use the correct search terms when looking for the restrictions.  Either way, you were there for me, so thank you again for all your help :)

Naomi >^,,^<

The second link: How can I create multiple lines in the Invoice, Purchase, Journal and other tables? explains how FQSavetoCache works with a lot of detail. A TRUE setting of "FQSaveToCache" instructs QODBC to take the values from your transaction line INSERT statement and hold them for later processing, but not to save them to QuickBooks yet. When QODBC receives the final transaction where the cache is set to 0 or FALSE or a header INSERT, the contents of the current INSERT statement will be combined with all of the previous INSERT statements held in the cache for this connection, and saved as a batch into QuickBooks.

QODBC maintains a connection for each application using the driver, and this cache is specific for each connection, so multiple applications or users of QODBC will not interfere with the cached transactions of other users. There is no set limit to the number of lines that can be cached for a single transaction, other than what QuickBooks would limit you to.

Oh, yup.  That second link was exactly what I was looking for!  I meant that I didn't find it on my own before, and that your initial response was right on the money :)

I also figured out that I can add a second invoice line item after the fact just by copying the transaction number of the initial invoice line item.  (I'm sure that's somewhere around here too...)  So now I'm off and running!  I think this driver is *exactly* what I needed to make my application do what I want it to do!  Thanks for the tool.  I'm lovin' it :) 

Nomi >^,,^<