Computer Knowledge: Database Concepts and Its Components for Competitive Exams

Database Concepts

A database is a collection of logically related information n an organised way so that it can be easily accessed, Managed and updated. Some other operations can also be performed on database such as adding, updating and deleting data. A database could be simple as a single text file with a list of names or it could be complex as a large bunch of text files including some data.

In database, data can be entered through input devices such as keyboard, mouse, touch-screen, etc. Some examples of database are telephone directory, railway timetable, books catalogue, equipment inventory, etc,.

Fundamentals of Database:

For defining database, two terms, which are used frequently with database, should be known.

Data: These are raw and unorganised facts that need to processed such as digital representation of text, numbers, graphical images or sound. Data refer to the values physically recorded in the database e.g., a student's text score is one piece of data.

Information: When data is organised, processed, presented or structured in given context to make it useful or meaningful, it is called information. Information refers to the conclusion or meaning drawn out of it. e.g., the class's average score is the information that can be concluded from the given data.



Types of Database

Database are of three types, namely

1) Network Database: In this type of database, data is represented as collection of records and relationships among data are represented as links.

2) Hierarchical Database: In this type of database, data is organised in the form of trees with nodes. Nodes are connected via links.

3) Relational Database: Relational database is also known as structured database in which data is stored in the form of tables. Where, columns defines the type of data stored in the table and rows defines the information about the data.

Components of a Database:

A database consists of several different components. Each component listed, these are  called an object. In one single file, you can divide your data into separate storage parts (Containers) called tables. View, add and update table data by using query's or on-line command forms. find and retrieve the data you want by using queries and analyse or print data in a specific layout by using reports.

Database components are described below;

Tables: Tables are the building blocks or relation of any relational database model where all the actual data is defined and entered. Tables consists of cells at the intersection of records (rows) and fields (columns). Different type of operations are done on the tables such as storing, filtering, retrieving and editing of data.

Field: A field is an area (within the record) reserved for a specific piece of data. e.g., student number, student name, address, city, state, phone number, current address etc., Field of a table is also known as column.

Record: A record is the collection of data items of all the fields pertaining to on entity i.e., a person. company, transition etc. Record of a table is also known as row or a tuple and the number of records in a relation is called the cardinality of that relation.

Queries: Queries are basically questions based on the data available in a database. A query consists of specifications indicating which fields, records and summaries a user want to fetch from a database. Queries allow you to extract data based on the criteria you define.

Forms: Although you can enter and modify data in datasheet view of tables but you neither control the user's action very well nor you can do much to facilitate the data-entry process. To overcome this problem, forms are introduced.

Reports: When you want to print those records which are fetched from your database, design a report. Access even has a wizard to help produce mailing labels.