An Introduction To The Fundamentals Of Database Systems
Database technology and database systems play an important role in almost all fields in which computers are used. Before we can understand how database systems work, we need to be aware of the fundamentals of database systems. These fundamentals are introduced below in the form of simple concepts.
A database is an ordered set of related data elements intended to support the information needs of a business organization and designed to be shared by multiple users. It can be viewed as a data repository that is defined once and is accessed by various users simultaneously. It is internally consistent and logically coherent. Its design is conceived with a specific purpose in mind.
A database system contains not only the database but also the data structure constraints (meta-data) and descriptions. The data definition is separated from the application program itself. In a database system approach, the data definition is stored in the system catalog and not in the application program. This helps because no change is then needed to be made in the programs even if the data structure undergoes a change.A database management system (DBMS) is a set of programs that enable database users to create, maintain, and control access to the database. The main objective of a DBMS is to provide an efficient and convenient environment for storage in and retrieval from the database of relevant information. An application program such as an SQL query is used to access the data stored in the data by sending requests to it.
A database system supports multiple views of data. This helps to provide access to only relevant views of data to different users and helps keep the security and confidentiality of data intact. An efficient database system allows many users to simultaneously access a database by implementing concurrency control.
An efficient database system must have the following features.
It must have data sharing capability so that the whole organization can benefit from a given amount of data by producing more information. It must provide capabilities to define and enforce data type and uniqueness constraints.
It must be equipped with the requisite security features to enforce user and password based authorization to restrict unauthorized access of data from a database. Different users must be provided different levels of access privileges. A specific user may be authorized only access to data, whereas another authorized user may be provided both access and data modification privileges.
The most used and popular DBMS in the world is the relational database management system (RDBMS). It uses the relational data model and uses the Entity-Relation (ER) concept. It uses normalization of tables to ensure that there is no data redundancy. It uses primary and foreign keys to control access to tables in the database and uses indexing to make faster searches for relevant data from the database.
The above introduction to the fundamentals of database systems is being wrapped up by informing that the latest DBMS in the world is the object oriented database management system (ODBMS). It is still under development.