Database architecture deals with design and development of programs that meets the requirement of users to access data in database. Database architecture is logically divided in two parts.
- Two tier architecture
- Three Tier Architecture
Two Tier Database Architecture:
Two tier architecture is used for the applications programs that runs on client side. This means clients can directly communicate with database without presence of some kind of middle ware.
An Interface called ODBC (Open Database Connectivity) provides an API that allow client side program to call the database. Most DBMS vendors supply ODBC driver for their database.
ODBC was originally developed by Microsoft and Simba Technologies during the early 1990s, and became the basis for the Call Level Interface (CLI) standardized by SQL Access Group in the Unix and mainframe field.
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It allows direct communication between client and server hence it is faster as compared to 3 tier or n-tier database architecture. In this architecture, each client must have ODBC driver installed on it in order to communicate with database server.
Three Tier Architecture:
Three tier client server database architecture is most common architecture in web application. In case of web applications, users do not directly request to database server, instead these request to web servers.
Web Servers in turn talk with database server with the help of Application server and return the web page back. Application Server not only communicate with database server but it also runs business logic regarding the web program.
There is intermediate layer that directly communicate with database server and return result’s to clients. That intermediate layer is Application Server.
