Using a data as unique identifier

Hi ,I am collecting data of breast cancer patients .Multiple people will be entering data.
I want to keep the hospital number as unique identifier so that i can avoid duplicate entries.
Please guide me how to do this .

Welcome to the community, @gomathishankar! Maybe these support articles Dynamic Data Attachments and Pull Data Functionality in KoboToolbox should help you achieve your goals to avoid duplicate entries when collecting data at the enumerators end.

Thank you so much.

Actually I am beginner and the suggested solutions are too complex for me.
Tools like redcap and epicollect have feature called as " unique identity label " in the form builder when we add a data label. Having a feature like that will make it easy for beginners like me.I have attached a screenshot for your reference. Kindly do the needful.Thank you.

epicollect unqiue data label

@Kal_Lam .Can you please check this suggestion.

The above screenshot is from epicollect.