DBMS 3-tier architecture divides the complete system into three inter-related but independent modules as shown in the above image(cover image).
Presentation layer / User layer✨✨✨: This tier is presented before the user who knows nothing regarding the other existing complex databases underneath. This tier can provide multiple views of the databases, generated by the application residing in the application tier.
Application tier✨✨: This is the middle-lined tier between the database and the presentation tier and acts as a connection between the end-user and the database. This tier holds the programs and the application server along with the programs that could access the database. This is the last layer that the users are made aware of . It provides a complete abstraction to the database layer.
Database tier✨: This tier holds the primary database along with all the data and the query language for processing. The relations of data with their constraints are also defined at this level.
✋ Enhanced scalability.
✋ data integrity.
✋ complexity of implementation and communication between client and server.