Data Base Management Systems

Data Base Management Systems


What is a Data Base ?

Data base is an any collection of data or information. Data bases support to store and manipulate to data.

What is a Data Base  Management Systems(DBMS) ?
       DBMS  used for define, manipulate, retrieve and mange data in a database. DBMS is widely used in Banking,Finance, Airlines, Telecommunication, Education and other industries.

DBMS is the software which is used to manage database.
     EX;   

• MySQL
• SQL Sever
• Oracle     
• Microsoft Access
• MariaDB
• PostgreSQL 
• FoxPro
• dBase

Characteristics of DBMS;

• Realistic
• Data storage
• Multi-user access control
• Data backup and recovery
• Data security management
• Data presentation and reporting
• Relationship among entities and tables
• Remove redundancy and integrity  
• ACID - (Atomicity, Consistency, Isolation, Durability) 

There are various category of users in DBMS;

• Application programmers

The application programmers who write programs to interact with databases

• Database administrators(DBA)

DBA is responsible for managing the entire DBMS

• End-user

People who interact with the DBMS for conduct various operations on database like retrieving, updating, deleting, etc.

Four types of DBMS systems;

1. Hierarchical DBMS 

In a hierarchical database model, data is organized into a tree like structure. Data is stored in a parent-children relationship nodes. A parent can have multiple children. Each child record has only one parent.

2. Network DBMS  

Network structure use to crate relationship between entities. This type of DBMS looks more like a cobweb or interconnected network of records.

3. Relational DBMS

Relational databases are the most popular and widely used databases. 
Ex: Oracle, SQL Server, MySQL, SQLite
In here the relationship among data is relational and data is stored in tabular form of columns and rows.

4. Object-Oriented DBMS

Object-oriented DBMS use small, recyclable separated of software called objects.
 

Advantages of DBMS;

• Data can be share between multiple users  even same time
• Minimize data redundancy
• Protect data from unauthorized users
• Users can easily create, insert,update, delete and retrieve data
• Backup and recovery data

Disadvantages of DBMS;

• Data base management systems can be complex
• Higher cost
• Higher impact of a failure
• Technical staff is required who understand DBMS
• Sometimes a DBMS requires extra disk storage for the data and  dedicated machine for better performance of database.  
• Frequency upgrade or replacement