You can execute data modification statements only if you have the proper permissions on the database tables you want to modify.
The database administrator and the owners of database objects use the GRANT and REVOKE statements to decide who has access to which data modification functions.
To insert data, you need INSERT permission for that table or view. To delete data, you need DELETE permission for that table or view. To update data, you need UPDATE permission. The DBA can insert into or delete from any table. The owner of a table has INSERT, DELETE, and UPDATE permission on it.
Permissions can be granted to and revoked from individual users, roles, or the PUBLIC role.