Evolution of Database Management Systems

What is a Database Management System (DBMS)?

• A DBMS is a group of tools that enable users to access databases and manage, update, report, and relate data.
• It helps to reduce issues with data integrity, data redundancy, and data sharing.
• A DBMS is mainly software; it is not an information system.

Evolution of Database Management System

• The primary goal of a database is to efficiently store and retrieve data.
• Databases evolved through the following stages:
  • Flat Files (1970s-1990s): simple, but had drawbacks in terms of data redundancy and access complexity.
  • Hierarchical DBMS (1970s-1990s): structured data in a parent-child relationship, but was rigid and had trouble handling intricate data structures.
  • Network DBMS (1970s-1990s): handled many-to-many relationships, but was difficult to maintain.
  • Relational DBMS (1980s-present): organizes data into tables with rows and columns, became the most widely used due to its flexibility, data optimization, and support for a wide range of processes.
  • Object-Oriented DBMS (1990s-present): stores information as objects, handled multiple data types and complex behaviors efficiently.
  • Object-Relational DBMS (1990s-present): combined relational and object-oriented features, offered rapid access speed and enormous store capacity.
  • Web-Enabled (1990s-present): databases with internet-based management and accessibility, enabling remote data administration and availability.

Components of a Database

• Hardware: the actual electrical equipment that serves as an interface between computers and real-world systems, such as hard drives and computers.
• Software: a collection of programs used to manage and govern databases, consisting of the operating system, network software, database software, and apps that access and exchange data with other users.
• Data: processed and arranged from unprocessed facts to make information more relevant, with two DBMS levels of data independence:
  • Physical-level data independence: changes to the internal schema can be made without necessitating changes to the logical schema.
  • Logical-level data independence: ensuring that there is no need to modify the application software when adding or deleting fields.

Database Architecture

• The structural layout and technique of a database system, providing the foundation of a DBMS.
• Influences the efficiency and efficacy of data management, specifying how data is accessed, stored, and arranged.
• A key feature of database architecture is the tier architecture, which divides capabilities into distinct levels or tiers, both physically and logically.