This is also called as ‘The Three-Schema Architecture’, which can be used to separate the user applications and the physical database
This is a lowest level, which describes how the data is actually stores.
Example: Customer account database can be described.
2.Logical Level: This is next higher level that describes what data and what relationships in the database.
Example: Each record type customer = record cust_name: sting; cust_city: string; cust_street: string; end;
3.Conceptual (view) Level: This is a lowest level, which describes entire database.
Example: All application programs