I have just gone through the cloud kit doc as in this link cloudkit but not getting clear about to modify database records for public database. As per this description in cloudkit framework.

Using Public Database, as specified in image by default data are world readable, owner writable. That means only owner can modify his data other user can only read? Suppose, using public database, user A can access records of user B, But can user A modify records of user B in same application.
Please suggest. Thanks.
