What are the types of Database Architecture? DBMS Tutorial

Types of Database Architecture

Understanding DBMS Architecture

A Database Management system is not always directly available for users and applications to access and store data in it. A Database Management system can be centralised(all the data stored at one location), decentralised(multiple copies of database at different locations) or hierarchical, depending upon its architecture.

1-tier DBMS architecture also exist, this is when the database is directly available to the user for using it to store data. Generally such a setup is used for local application development, where programmers communicate directly with the database for quick response.

Database Architecture is logically of two types:

  1. 2-tier DBMS architecture
  2. 3-tier DBMS architecture

2-tier DBMS Architecture

2-tier DBMS architecture includes an Application layer between the user and the DBMS, which is responsible to communicate the user’s request to the database management system and then send the response from the DBMS to the user.

An application interface known as ODBC(Open Database Connectivity) provides an API that allow client side program to call the DBMS. Most DBMS vendors provide ODBC drivers for their DBMS.

2-tier dbms architecture

Such an architecture provides the DBMS extra security as it is not exposed to the End User directly. Also, security can be improved by adding security and authentication checks in the Application layer too.


3-tier DBMS Architecture

3-tier DBMS architecture is the most commonly used architecture for web applications.

3-tier dbms architecture

It is an extension of the 2-tier architecture. In the 2-tier architecture, we have an application layer which can be accessed programatically to perform various operations on the DBMS. The application generally understands the Database Access Language and processes end users requests to the DBMS.

In 3-tier architecture, an additional Presentation or GUI Layer is added, which provides a graphical user interface for the End user to interact with the DBMS.

For the end user, the GUI layer is the Database System, and the end user has no idea about the application layer and the DBMS system.

If you have used MySQL, then you must have seen PHPMyAdmin, it is the best example of a 3-tier DBMS architecture.

Database architecture is logically divided into two types.

  1. Logical two-tier Client / Server architecture
  2. Logical three-tier Client / Server architecture

Two-tier Client / Server Architecture

It is used for User Interface program and Application Programs that runs on client side. An interface called ODBC(Open Database Connectivity) provides an API that allow client side program to call the dbms. Most DBMS vendors provide ODBC drivers. A client program may connect to several DBMS’s. In this architecture some variation of client is also possible for example in some DBMS’s more functionality is transferred to the client including data dictionary, optimization etc. Such clients are called Data server.


Three-tier Client / Server Architecture

It is commonly used architecture for web applications. Intermediate layer called Application server or Web Server stores the web connectivty software and the business logic(constraints) part of application used to access the right amount of data from the database server. This layer acts like medium for sending partially processed data between the database server and the client.


 

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