I just want to share a database with two or my websites. Each website has its own cpanel. Yes, I can manage all the databases using WHM, but with cpanel is different. Each website declared and named its database by adding to the domain prefix any string.
Why would someone have 1 DB andd connect to multiple sites ?
For easy access ?
1 DB has limits, it can be easily overloaded, not unless you wanted to have suspended hosting plan because the DB exceeded the limit.
When you say cPanel , cPanels can be with WHM aswell that is if it's into a VPS, I think you have a shared cPanel, WHM is disabled on Shared Hosting plans.
On a shared cPanel it is possible to have one DB and connect it with multiple sites but Godaddy won't support that since it can have lot's of issues, Suggested still is one DB per website.