Database Management System

Database Management System

What Is DBMS | Types Of DBMS | RDBMS | MySQL

Database Management System ( DBMS ) is a software application used to create , manage and administer the databases. The DBMS also provides the necessary tools required for the design and development of databases.

Database Management System ( DBMS ) is a vital component of most of the software applications . Whether you are working on a enterprise software development project or you may be developing a small website , the database design and development skills are needed in almost all software applications.

The  business corporations are  investing  huge amount of money for the collection , analysis  and  management of   large volumes  data which is  critically important  to support the day-to-day  business  operations  of the company .

 And  therefore  , the  database management professionals  are in great demand  having expertise in developing  the software applications to  handle the large volume of data  , designing the database and database administration .

Database Management System

Table Of Contents

Database Management System

What Is Data ?

Before we start discussion on the database , let us first understand the meaning of term data for a database design professional. The  data  is  the most  important  element  of any DBMS. And therefore , It is important to understand  what data means to the  database user , database  designers and  to the computer system  at  the hardware level  .

The term data  simply  means  recordable facts , observations  , factual information , set of values  and  figures  and  so on . For example if we are designing a database to store the employee data then all the employee related information ( Such as Name , Address , Designation , DOB , Salary ) will be stored as employee data.

What Is Data , DBMS

Database Management System

What Is A Data Processing ?

The  Data generally means raw data that needs to be collected  and cannot be used  directly  for  some  decision making . However, once the data is processed into  information , then it can be used  for some meaningful purpose such as decision making . Therefore ,  It said that Information  is  a  processed  data .

The  data  processing  essentially means manipulation of data  with  the help of  computers  and  a  software  . The  raw data is first  converted in to machine readable form  so that it can be processed  by the computer  as per the program instructions .

Data Processing

For example,  employee attendance data is processed with the help of payroll processing software to calculate employee salary every month.

The data processing  is  extensively used  for  Business , Engineering , Scientific  Research and practically in every industry  . Depending upon the volume of data  , High speed  computer systems  and the software applications designed to process the data are  used .

What Is A Database ?

A  Database is a computer based  record keeping system which is used to record , maintain and retrieve data .In other words , Database is an organized collection of  interrelated  records such  as  employee  database  OR  customer database.

The main purpose of database is to operate  and handle  large amount of information ( data )  by efficiently storing , retrieving  and  managing  the  data  in the  database .

What Is Database

The  database  is  a  key  component of  most  software applications  which are designed  to  store the  information about  some real world business entities such as  employee database , customer database ,  student database  and so on.

The database  is the well organized collection of  interrelated data  which makes it possible  to easily access , retrieve  and store the data for future use .  The  databases  are  created  , administered  and  managed  by using  any  DBMS  software .

Data Features
Database Features

Database Management System

What Is DBMS ?

The  DBMS  stands for Database Management system  which is a  software Or group of programs designed  to perform database operations  such as creating new database , administering  and managing the databases by performing various user specified database operations .

The DBMS allows the end users to perform various database operations such as create new records , save data , edit data , delete data , read and manipulate the data .

The database user interacts with the application program . The DBMS effectively functions as an interface between the application program  and the database. The DBMS also enforce certain constrains to ensure that the data stored is consistent and accurate .

What Is Database Management System , Database Management System

The DBMS provides the centralized view of the data that can be accessed simultaneously by number of database users . The Database can be accessed by either actual end user , database programmer or by database administrator .

The DBMS gives complete control to the database administrator to decide which data can be viewed by the user and operations that user can perform on that data . The database administrator can create the groups of database users and set access permissions .

The DBMS also provides an abstracted view of the database thereby completely hiding the complexities involved in how the data is actually physically stored into the database . The end user generally interacts with the database through application software interface.

Some of the most commonly used DBMS includes MySQL , Oracle , MS SQL Server , Oracle , IBM DB2 , MS Access , Maria DB , Mango DB , Postgre SQL and there are many more. These DBMS are based on the Relational Database Model hence referred as Relational Database Management System ( RDBMS ) .

RDBMS , MySQL
RDBMS , Commonly Used DBMS , Database Management System

Database Management System

DBMS Advantages

A  DBMS  is  integral  and  indispensible  part of almost all modern organizations  irrespective  of  the size  and scale  of the  business operations .    A  DBMS  offers  many advantages as compared to any traditional   computer  based  record keeping system .

  • Consistency Of Data
  • Improved Data Integrity
  • Data Backup And Recovery
  • Data Abstraction

Database Management System

Most Popular DBMS

DBMS Examples

The DBMS market is dominated by the top industry players . MySQL , Oracle And MS SQL sever continues to be the dominant players in DBMS market . The list is not in the order of ranking . Some of the most popular and widely used RDBMS include :

Database Management System

MySQL

MySQL is the most popular and extensively used  open source DBMS . MySQL is a Relational Database Management System ( RDBMS ) based on relational database model . MySQL is  extensively being used for providing database functionality to the  web based applications and websites.

Another major advantage of MySQL database is open source  ,  that means   the user has access to the source code under license ,  which  can  be modified as per  needs .  My SQL  also offers a paid  enterprise version , which offers some additional plug-ins , to augment the existing functionality .

MySQL with its proven track record of  performance , reliability , scalability and ease-of-use  has become  default  choice  for  some of the largest  web applications such as face  book , Twitter and YouTube.

Most Popular DBMS , Database Management Systems

Database Evolution

File System Databases Vs DBMS

The  first generation of   Databases were based on the collection of unrelated   files  . The  file system  based  database  was  logical extension of manual record  keeping ,  but it  was  a  computer based  record  keeping .

In  a file system database  , the files  were grouped  and  organized in folders . The file system databases  had many limitations . Any change made  in  file  structure , needed  a  corresponding change in the program  code   designed  to  operate  on these files .

A File system database is a DBMS that allows access to single files or a single tables at a time. The File System organizes the either in a single file or group of files stored on a local hard disk.

These files are not interrelated and it is difficult to establish relationship between these files . The file is referred as flat file when  the data is stored in a single file .

Database Management System

DBMS Characteristics

1. DBMS Can Handle Wide Range Of Data Types

The DBMS offers wide options for data types and  therefore, it is easier to model any real world database entity in DBMS .

2. DBMS Is ACID Compliant

DBMS Is ACID ( Accuracy, Completeness, Isolation, and  Durability ) Compliant . The DBMS can enforce constrains on user data and operations to ensure the accuracy and consistency of data in a database.

3. DBMS Allows Controlled Access

The DBMS allows to create different types of User groups and set different access permissions to these groups .

4. DBMS Allows To Define Relationships

The DBMS allows the database designers to define the logical schema of the database. The database designers can create logical entities such as table and establish relations between the tables .

5. DBMS Can Be Configured

The DBMS can be configured to support  complex  computer networks and system architecture such as multi-location distributed database operations without any technical issues  with concurrent database operations.

6. DBMS Provides Database Safety

The DBMS offers many features to ensure the data security and the  safety of the database such as back and recovery  which makes the life much easier for database administrators .

Types Of DBMS

Types Of Database Models

The  database design  approach  depends upon the database model being implemented. It is important  for  database design professional ,  to understand the different types of database models and  how these database models are  fundamentally different in terms of their design approach.

A  database model  is  a  type  of database  structure that  determines  the  logical structure of the database and fundamentally determines , the manner in which the data can be stored, organized and manipulated  within  a  database .

Most database management systems are built with  a particular database  model in mind and require their users to adopt that model . For  example,   MySQL   DBMS supports  only  “Relational Database Model” although  some DBMS  do  support  multiple database  models.

Hierarchical Database Model

The hierarchical  database model is based on  parent-child  relationship . It  is  a   database model  in  which , the data is organized  into  a  tree-like structure. The data is  stored  as records which are connected to one another through  links.

A  record  is  a collection of fields , with each  field  containing only one value. The entity type of a record defines , which fields the record  contains .

Network Database Model

The network database model was a progression from the hierarchical database model . The network database model was designed to solve some of the model’s problems such as  the lack of flexibility.

The network database model allows each child to have multiple parents . The network database model can handle needs  to model more complex relationships .

The main advantage of the network database model  as compared with the hierarchical model is the ability  to handle more complex relations such as many-to-many relations by allowing  records  to have  more than one parent .

Hierarchical Database Model , Database Management System
Network Database Model , Database Management System

Database Management System

Relational Database Model

The ‘Relational Database Model is the most commonly used model in the industry today. Some  of the  most popular RDBMS ( Relational Database Management System ) being used  are  based  on the relational model and that includes  MySQL , Oracle , MS Access and   MS SQL .

 A relational database is based on the relational model proposed and  developed by E.F. Codd  who was an English computer scientist  while he was working for IBM .

Relational Database Model , RDBMS
Relational Database Model Example

In  a relational database model  , the database is logically organized  as  group of related tables . Each table can have multiple rows and columns . A table is a collection  of  records  related  to  an  entity .

Each row in a table represents a record ( Tuple / Row ) which  consist  of number of data fields . A column  in a table  represents  an  attribute   for  a database  entity .

Database Management System

Object Oriented Database Model

The  Object Oriented programming ( OOP )  is a programming style that is associated with some fundamental design  concepts ,  which govern the manner in which a  program code is  organized  and  written  in OOP .

The  Object Oriented Programming ( OOP )   is an approach to software application development in which  all application components  are treated as objects and the actions performed by these objects.

An object is a component of a program that binds data and methods together . The methods  knows how to perform certain actions on the data and how to interact with other elements of the program. The Objects are the basic units of object Oriented  programming  .

Object Oriented Database Model
Object Oriented Database Management System

The Object Oriented Database Model ( OODM ) is based on the core concepts of Object Oriented programming and  provides  all  the features of  Object Oriented Programming ( OOP ) .

 In  OODMS , all the  database objects  are represented  in the form of objects . This  model  allows the database  designers ,  to easily model  complex  databases .

Database Management System

DBMS Architecture

The DBMS has become critical component of most business organizations , which helps the organizations to record and manage all business transactions . The selection of the suitable DBMS depends upon several factors and  the database system architecture is designed accordingly to meet the  needs of an organization .

The database system architecture is generally based on the client server architecture and the computer networking technology to provide the suitable  database system solution as per the needs of an organization.

The DBMS can be configured to meet the  database system requirements and   system architecture  is  designed to support such database system .

The client – Server Architecture  can  be categorized  into three  types depending upon the number of tiers ( Presentation , Business And Database Tier )  present on one computer . The  most commonly used client server  architecture  include  :

  • Single Tier Architecture
  • Two Tier Architecture
  • Three Tier Architecture

DBMS Architecture

Single Tier Architecture

In  Single tier client server architecture  all the three layers  / tiers / logic  ( Presentation tier  ( GUI Interface ) , Business tier ( Application Software )  and Data tier ( Database )  resides on the same  computer  system  .

The presentation tier is a software application that end user interacts to communicate with the database . The business tier generally resides on the server and holds the business logic. The database tier again resides on the server where the data is actually stored into the database.

DBMS Single Tier Architecture Diagram

DBMS Architecture , Single Tier Architecture

DBMS Architecture

Two Tier Architecture

In  two tier client server architecture , the Presentation tier  ( GUI Interface ) resides on the Client system whereas the remaining two tiers i.e Business tier ( Application Software )  and Data tier ( Database )  resides on the same  computer  system  .

DBMS Two Tier Architecture Diagram

DBMS Architecture , Two Tier Architecture , Database Management System

DBMS Architecture

Three Tier Architecture

In  three tier client server architecture all three layers / logic / tiers resides on a separate system.  The front end Presentation tier  ( GUI Interface ) resides on the Client system , the Business tier ( Application Software )  and Data tier ( Database )  resides on the separate  computer  system  .

DBMS Three Tier Architecture Diagram

DBMS Architecture , Three Tier Architecture , Database Management System

Database Management System

Logical And Physical Data Independence

What Is Data Independence ?

The database management system allows the database designers both logical and physical data independence . The database schema defines the view of the database at three levels that is external schema , logical schema and internal schema .

The data independence is the ability to modify a schema definition in one level ( either Internal , logical Or external schema ) without affecting a schema definition in the next higher level.

DBMS Three Schema Architecture , Data Independence , Database Management System

The logical data independence provides a simplified view of the database and the end user need not worry about complexities of  how the  data is physically being stored  and  any changes in the hardware ( Storage devices ) .

The end user interacts with the application program which acts as an interface between the user and DBMS. The application program makes use of the  DBMS API ( Application Programming Interface ) and therefore, the application program doesn’t require any modification due to changes in the database structure .

Database Management System

DBMS

Database System Environment

The database system environment refers to a set of components used within a database system that define and control the collection, storage, management and  use of  data . Each  component  performs a specific  role  within  a  database system  environment.

A DBMS structure usually consist of number of  components ( Also referred as modules ) depending upon DBMS architecture and the relationships between these components . The DBMS software might consist of  several modules . Each module or component is assigned to perform a specific  database operation .

DBMS Environment Components

Some of the functions of the DBMS are supported by the operating system ( OS ) to provide basic services and DBMS is built on top of it . The physical data and system catalogue  are stored  on  a  physical  storage  disk.

RDBMS

Relational Database Management System

The Relational Database Management System ( RDBMS ) is the most commonly used databases in the industry today. Some  of the  most popular DBMS being used  are  based  on the relational model  that includes MySQL , Oracle  and   MS SQL Server .

A relational database is a database that is based on the relational model . The Relational Database Model was  proposed and  developed by E.F. Codd  who was an English computer scientist  while working for IBM .

Relational Database Model , RDBMS
Relational Database Model Example , RDBMS

In  a relational database model  , the database is logically organized  as  group of inter related tables . Each table can have multiple rows and columns . A table is a collection  of  records and  represents a database entity .

Each row in a table represents a record ( Tuple / Row ) which consist of number of data fields . The  columns  in a table  represents  an  attribute  for  an  entity . The intersection of row and column is referred as field which actually hols the data.

Relational Database Table , Database Management System , RDBMS

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