An user or an application can not directly interact with the Database Management System. A DBMS can be centralized (all the data stored at one location), decentralized (several copies of data resides at different locations) or hierarchical depending upon its architecture. So any user or an application can not directly retrieve or store data in the database.
A good DBMS architecture supports in designing, development, implementation and maintenance of a database. A good DBMS architecture ensures the securities and efficient access to the database.
1-Tier DBMS is the most simplest database architecture in which client, server and database all resides on the same system. Whenever you install any database in your computer and access to communicate directly with the database by writing some SQL queries it is said to be 1-Tier architecture.
Database Architecture is logically divided into two types.
In this architecture, clients communicate with the server with the help of an application which lies between client and the server. The interface between client and server is known as Application layer interface which is responsible for the communication the user’s request and server’s response.
This type of architecture provides faster access to the data retrieval and security by checking the authentic request check at application layer.
3-Tier architecture is the commonly used architecture in the web applications world. It is an extension of 2-tier application. Users are interacted with more advanced GUI based interface, which acts as a presentation layer.
So, here in diagram you will see 3 tiers. Client Tier which is presentation layer. Business Logic Tier – In this layer, functional logic, constraint and rules are performed before sending the data to the user or to the database.