# Comparing subform data when subform has multiple elements property checked

**URL:** <https://forum.flowable.org/t/comparing-subform-data-when-subform-has-multiple-elements-property-checked/6838>\
**Category:** Flowable Designer\
**Created:** [September 25, 2020, 8:17am UTC](https://forum.flowable.org/t/comparing-subform-data-when-subform-has-multiple-elements-property-checked/6838 "2020-09-25T08:17:57Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![ritikamehta394](https://avatars.discourse-cdn.com/v4/letter/r/e47c2d/32.png) [@ritikamehta394](https://forum.flowable.org/u/ritikamehta394)\
**Post date:** [September 25, 2020, 8:17am UTC](https://forum.flowable.org/t/comparing-subform-data-when-subform-has-multiple-elements-property-checked/6838/1 "2020-09-25T08:17:57Z")

</div>

I have a subform which stores it’s data in a single element and allows multiple elements to be stored.I e. Subform variable becomes a list.Now i want to ensure that no 2 subform have the same data in them.

Eg. I have a subform which contains name and age and i have this data to be filled for 5 students  
I fill in the data for 1st student with name= Tom and age = 10  
When i add using the add button on the subform i should be allowed to enter values of name as anything except Tom , i need to apply a custom validation expression.  
How to write this expression in such a case