Introduction to Databases

A collected information which is in an organized form for easier access, management, and various updating is known as a database.

Before going into a further discussion of databases, we must have a prior knowledge of exactly what is a DATA? Data can be defined as a collection of facts and records on which we can apply reasoning or can-do discussion or some calculation. The data is always easily available and is in plenty. It can be used for processing some useful information from it. Also, it can be in redundant, can be irrelevant. Data can exist in form of graphics, reports, tables, text, etc. that represents every kind of information, that allows easy retrieval, updating, analysis, and output of data by systematically organized or structured repository of indexed information.

Containers having a huge amount of data are known as databases, for example, a public library stores books. Databases are computer structures that save, organize, protect, and deliver data.

Any system that manages databases is called a database management system, or DBM. The typical diagram representation for a database is a cylinder.

Inside a database, the data is recorded in a table which is a collection of rows, columns, and it is indexed so that to find relevant information becomes an easier task. As new information is added, data gets updated, expanded and deleted. The various processes of databases create and update themselves, querying the data they contain and running applications against it.

The are several different types of database models have been developed so far, for example, flat, hierarchical, network and relational. These models describe the operations that can be performed on them as well as the structure of the conforming databases. Normally there is a database schema which describes the exact model, entity types, and relationships among those entities.

 Flat Databases have the following characteristics −

• simple
• long and dominant
• useful for very small scale and simple applications.

A Relational Database has the following characteristics −

• organizes data such that it appears to the user to be stored in a series of interrelated tables
• used for high-performance applications
• efficient
• ease of use
• ability to perform a variety of useful tasks