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What is database and SQL?

In simple words data can be facts related to any object in consideration.For example your name, age, height, weight, etc are some data related to you. A picture , image , file , pdf etc can also be considered data.

What is a Database? 

Database is a systematic collection of data. Databases support storage and manipulation of data. Databases make data management easy. Let's discuss few examples. An online telephone directory would definitely use database to store data pertaining to people, phone numbers, other contact details, etc.Your electricity service provider is obviously using a database to manage billing , client related issues, to handle fault data, etc. Let's also consider the facebook. It needs to store, manipulate and present data related to members, their friends, member activities, messages, advertisements and lot more. We can provide countless number of examples for usage of databases .

What is a Database Management System (DBMS)?

Database Management System (DBMS) is a collection of programs which enables its users to access database, manipulate data, reporting / representation of data .
It also helps to control access to the database.
Database Management Systems are not a new concept and as such had been first implemented in 1960s.Charles Bachmen's Integrated Data Store (IDS) is said to be the first DBMS in history.
With time database technologies evolved a lot while usage and expected functionalities of databases have been increased immensely.

Types of DBMS: 

Let's see how the DBMS family got evolved with the time. Following diagram shows the evolution of DBMS categories.

Hierarchical - 

This type of DBMS employs the "parent-child" relationship of storing data. This type of DBMS is rarely used nowadays. Its structure is like a tree with nodes representing records and branches representing fields. The windows registry used in Windows XP is an example of a hierarchical database. Configuration settings are stored as tree structures with nodes.

Network DBMS - 

This type of DBMS supports many-to many relations. This usually results in complex database structures. RDM Server is an example of a database management system that implements the network model.

Relational DBMS -

This type of DBMS defines database relationships in form of tables, also known as relations. Unlike network DBMS, RDBMS does not support many to many relationships.Relational DBMS usually have pre-defined data types that they can support. This is the most popular DBMS type in the market. Examples of relational database management systems include MySQL, Oracle, and Microsoft SQL Server database.

Object Oriented Relation DBMS - 

This type supports storage of new data types. The data to be stored is in form of objects. The objects to be stored in the database have attributes (i.e. gender, ager) and methods that define what to do with the data. PostgreSQL is an example of an object oriented relational DBMS.

What is SQL?

Structured Query language (SQL) pronounced as "S-Q-L" or sometimes as "See-Quel"is actually the standard language for dealing with Relational Databases.
SQL programming can be effectively used to insert, search, update, delete database records. Although SQL is an ANSI (American National Standards Institute) standard, there are different versions of the SQL language.
However, to be compliant with the ANSI standard, they all support at least the major commands (such as SELECT, UPDATE, DELETE, INSERT, WHERE) in a similar manner.
Note: Most of the SQL database programs also have their own proprietary extensions in addition to the SQL standard!

What Can SQL do?

  • SQL can execute queries against a database
  • SQL can retrieve data from a database
  • SQL can insert records in a database
  • SQL can update records in a database
  • SQL can delete records from a database
  • SQL can create new databases
  • SQL can create new tables in a database
  • SQL can create stored procedures in a database
  • SQL can create views in a database
  • SQL can set permissions on tables, procedures, and views


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