@SundarSritharan , You must have some identifier for each record of data
ingested based on which data is linked to profile, provided you have
enabled the profile option in dataset. You can make use of merge
policies to stitching and mapping, refer this document :
https://experienceleague.adobe.com/docs/experience-platform/profile/merge-policies/overview.html?lang=en#
RegardsSkand