InfoPath Dev

I am trying to setup a Data Connection that will query that will check for duplicate entries in a Sharepoint list. 

 Scenario:

 Form contains a field called "Protocol Number" which can not be duplicate entry........ meaning, if the number already exist in the Sharepoint list.  I created a data connection called "Duplicate Check" which goes to the list and receives data.  This is where i am stuck.  Do I select the field (Protocol Number) and place a rule on it to query the connection?  I tried this but didnt see how it would look for duplicates.  Can someone explain how this works?

OR better yet, I have QRules 2.3 (need update), is this a better way?  Does anybody know how i would set this up?

thanks

You can use the command FilterOvwsrv in qRules for this. Basically, you would be filtering the SharePoint data connection for Protocol Number to return only rows where Protocol Number in the ShP list = the Protocol Number entered by the user. If the qRules command finds a match (look at the Success and Result nodes in the QdabraRules 2DS) then you know you have a duplicate and can add some additional actions, as desired.

Here is a tutorial on using this command.

Hope this helps!

sir, is this something i can put into the primary data connection or do I need to have a secondary connection?  Realize that the user submitting info but first checking for duplicates.  This is normally done on the primary submit.

Just wanted to update this with the results from our phone call.

An owssvr.dll data connection was added to the form. We used qRules FilterOwssvr and when the field changes, we run the command to return any items from the list that match that number. We added data validation to the field so that it will fail validation if the owssvr.dll data connection returns any rows (thus, the number already exists).