In Depth Notes on Database System Concepts

Centralized and Client/Server Architectures for DBMSs

• Centralized DBMS Architecture:

  • Older systems used mainframes to handle all processing and DBMS functionality.

  • Users accessed DBMS via terminals (limited processing capabilities).

• Transition to Client/Server:

  • As technology evolved, processing began to shift to clients (PCs and mobile devices).

  • Led to the development of the Client/Server DBMS architecture.

Client/Server Architecture

• Defined to manage environments with many connected client machines and specialized servers.

• Components:

  • Clients: User machines with interfaces running applications.

  • Servers: Machines providing services like file access, database access.

• Specialized Servers Examples:

  • File servers, Print servers, Web servers, Email servers.

Two-Tier Client/Server Architectures for DBMSs

• Features:

  • User interface and application programs run on the client side.

  • Database querying and transaction processing handled on the server side.

• Communication:

  • Clients connect to the DBMS using ODBC (Open Database Connectivity) for interaction.

  • JDBC (Java Database Connectivity) for Java applications.

• Advantages:

  • Simplicity and compatibility with existing systems.

Three-Tier and n-Tier Architectures for Web Applications

• Three-Tier Architecture:

  • Introduces an application server to mediate between client and database server, improving security and functionality.

  • Layers:

  • Presentation Layer: User interface.

  • Business Logic Layer: Application processing rules.

  • Database Services Layer: Where data management occurs.

• n-Tier Architectures:

  • Further division of layers, where one layer can operate independently (can increases scalability and flexibility).