how to check row already exist in repeating table in infopath?

Hello I have repeating table on my infopath form. It is bound with xml file through web 开发者_Python百科service. my form have submit button. I am able to submit data from infopath for to xml document via web service. I want to validate my repeating table to avoid duplicate records. how to do this validation. ? please guide me I am new for this.

You must use validation rule.

1. You must select specific field of repeating table.
2. Add validation rule to it.

3. Select the expression and add rule:

    ../my:fzScopeName = ../preceding-sibling::my:fzItem/my:fzScopeName
   

   or

   ../my:fzScopeName = ../following-sibling::my:fzItem/my:fzScopeName
   

Note that: My field name is fzScopeName and fzItem is parent it, as same repeating table structure. see this image