DATABASE MANAGEMENT

DATABASE MANAGEMENT

Firstly database is simply a place to store information or a collection of information which is organized alphabetically. The main role of database is to collect, organize store, and retrieve the information when needed, for example in collage or food production. A software which is used to manipulate the database is called database management system. There are 4 components of database: data items which is a distinct piece of information, relationships which represents a correspondence between different data, constraints this one I still don’t understand it. I have to read about it again and lastly schema; schema describes the organization of data and relationships within the database. For example in this three courses the schema will tell u the data for the student x in these three deferent subject. It will relate all information for student x from different subjects

The student x has got 30 in math, 25 in English and 73.

DBMS is database management system and how it function is very important. The five main functions of DBMS are: 1. define, create and organize a database: the DBMS establishes the logical relationships among different data elements and also defines schemas and subschemas using DDL.

2. Input data: it performs the functions of entering the data into the database through an input device (like data screen, or voice activated system) with the help of the user.
3Process data: It performs the function of manipulation and processing of the data stored in the database using the DML.
4. Maintain data integrity and security: It allows limited access of the database to authorized users to maintain data integrity and security.
5. Query database: It provides information to the decision makers that they need to make important decisions. This information is provided by querying the database using SQL.

In order to create database we have to use database models, they tell us how data can be classified or organized in a database. There are three database models: “entity” which symbolizes or represents   data in the real world, it is always in raw. The second entity is: “attribute” which represent the characteristic of the entity (always in column). The last one is relationship; describes the relationship in entities.

Lastly I studied three types of database: hierarchical, network and relational database. The first one allows “one to many” relationship, the 2^nd allows many to many and lastly relational allows one to one relationship between entities. This one is mostly used in small organizatons.