Views allow you to hide data complexity. Views help you maintain naming sanity. Index entries for a table allow Oracle rapid access to the data in your tables. A synonym is an alternate name for an object in the database. Think of a synonym as a nickname for an object.
Grants are privileges given out by owners of objects, allowing other users to work with their data.
A role is a group of privileges that are collected together and granted to users. Once privileges are granted to a role, a user inherits the role's privileges by becoming a member of that role. This way, instead of updating every user's account on an individual basis, you can just manage the role. Select The word select followed by what you want to see. This is mandatory.