How different levels of access authentication are classified? | OBIEE

The levels are in number of four and their role is to block access to various databases or tables: 1) Operating level- without this authentication no one can get access in the application as this is the highest level of restriction. 2) Table- every physical table can be restricted. 3) Database- This can give total or partial access to the database by a user and a password to the user or can restrict all the access. 4) LDAP- or Lightweight Directory Access Protocol it provides access limits for various folders or directories.