Client server database consists of two logical components. One is “Client” and the other one is “Server”. Clients are those who send the request to perform a specific task to the server. Servers are normally receive the command sent by the clients, perform the task and send the appropriate result back to the client. Example of client is PC where as the server is a large work station. The Client machine runs own copy of an operating system. It runs one or more applications through client’s CPU and memory. But server runs a database management system which manages the whole database.
Client system vs Server system
A client system is that who sends the request to the server system and the server system has to response the request as result. A client system is managed by users where as the server system is managed by a computer expert. No need of a computer expert in client system. The client system is a system on which the results are prepared and displayed whereas the server system is a system in which the information is prepared for the client.
Types of client server architecture
Normally, there are three types of client server architecture available in database management system. These are listed below.
(a) Single tier client server computing model
(b) Two tier client server computing model
(c) Three tier client server computing model
Single tier client server architecture.
Single tier architecture is the first type of client server computing model. In single tire client server computing model, the client server database system used on a personal computer. In single tire system, the database is centralized, which means the DBMS software and the data in one location and the dumb terminals were used to access the database management system.
Two-tier client server computing model
Two-tier client server architecture is the second type of client server computing model. It uses two computers and one client/server system. At the early stages, client server computing it was called two-tier computing model in which client is considered as data capture and validation tier and server was considered as data storage tire.
Problems in two tier architecture
In 1990s, when applications were more complex and used with hundreds or thousands of end users, the two tier server model could not meet the need of the enterprise.
(a) An efficient client requiring considerable resources on client’s computer to run effectively. This includes disk space, RAM, CPU.
(b) Client machines require administration which results overhead at the server end.
Three tier architecture.
Three tier architecture is the improvement over two tier architecture. Three tier architecture has three layers. The first layer is the user interface which runs on client system. The second layer is called the application server . It is used for business logic and data processing. The third layer is known as database server. It is a database management system which stores the data as needed by the middle layer.
Advantages of client server database system
The advantages of client server database system are as follows:
(a) Client server system has cost effective platforms to support the applications.
(b) Client offers graphical menu driven interface, which is superior to the traditional command line.
(c) Client server environment facilitates in more productive work by the users and efficient use of existing data.
(d) Client server database system is more flexible.
(e) A single database on server can be shared across several distinct client systems.
Disadvantages of client server database system
There are some disadvantages in client server database system. These are
(a) In initial phases, the programming cost is high.
(b) There is a lack of management tools for performance monitoring and timing.
Difference between DBMS and RDBMS
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