SQL Introduction

What is SQL:

• SQL is an abbreviation of Structured Query Language.
• It enables us to handle databases.
• SQL achieved the standard of the ANSI( American National Standards Institute) in 1986 and emerged as the standard of ISO(International Organization for Standardization) in 1987.

What we can do using SQL?

• -  We can fetch data from a database.
• -  We can run quereis against a database.
• -  We can insert new records in the database.
• -  We can edit and update pre-existing records.
• -  We can delete the record in the database.
• -  We can also create new databases through SQL.
• -  We can also insert tables in the database.
• -  We can create store procedures in database using SQL.
• -  We can create views in the database using SQL.
• -  Permissions on database tables,views and procedures can also be set by SQL.

How to use SQL in our website?

In order to show the data in our web page from Database we need :

• A Relational Database Managment System application such as : Microsoft Access, Microsoft SQL Server,My SQL.
• The knowledge of the server side scripting language such as PHP or ASP.
• the knowledge of the HTML/CSS to design the page.
• the knowledge of SQL to get / insert the data according to our need.

What is Relational Database Management System?

Relational Database Management System is abbreviated as RDBMS and it is the basis of all the modern database management systems such as MYSQL, MS Acess, IBM, DB2 etc.

In RDBMS data is stored in the form of objects called tables.A table has rows and cloumns in it, which shows collection of releated data entries.

Look at the example below , we are getting all data from customers table by running the query below.

SELECT * FROM Customers;

Here are results from Customers table.