Hi Akhilesh,
We have the option "View where used" at table level, not at data store level. If the password is changed in the back end you can simply edit data store configuration and update the password. That should not have any impact on any no.of jobs using objects in it.
If you still want to check the usage of the objects in that data store, you will have to manually navigate through all the tables and check view where used.
Hope this answers your query.
Thanks and regards
Abdul Majeed Mohammed