The DBMS architecture has evolved from centralized system to the modern distributed database.The modern DBMS is based on client server architecture.the majority of the user’s DBMS are not present at the site.but are connected it through a network. on server machine ,the database system runs,wherever on client machines remote database user work.
The Database Application are usually partitioned into 2-Tier Architecture or 3-tier Architecture.
2-Tier DBMS Architecture
In 2-tier DBMS architecture,the Application is partitioned into a component that resides at the client machine,which invokes database system functionality at the server machine through query language statement.Application program interface standards are used for interaction between the client and the server.
3-Tier DBMS Architecture
In a 3 tier architecture the client machine act as a front end and doesn’t contain any direct database call, instead, the client and communicates with an application server, usually through a form of interface, application server intern communicates with a database system to access data. the business logic of the application, which says what action to carry out and under what conditions, is embedded in the application server instead of being distributed across multiple clients. 3 tier are more appropriate for large applications info application that run on the web.