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SQL Tutorial
INTRODUCTION TO SQL
SQL stands for Structured Query Language. It is an ANSI (American
National Standards Institute) standard computer language. It is used
for storing and retrieving data in an organized and efficient manner
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** SQL is easy to learn**
SQL works with database programs like MS Access, DB2, Informix, MS SQL
Server, Oracle, Sybase, etc...,
Records : It is a collection of fields
Tables :It is a collection of records
Database ( it is a collection of Tables)
Each table is identified by a name
Below is an example of a table called "Employee":
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| LastName | FirstName | Age |
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| Clove | Peter | 34 |
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| Waugh | Steve | 58 |
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| Clove | Mark | 65 |
-----------------------------------------------------------------------------
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Data Manipulation Language (DML)
These query and update commands together form the Data Manipulation
Language (DML) part of SQL:
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SELECT - extracts data from a database table
* UPDATE - updates data in a database table
* DELETE - deletes data from a database table
* INSERT INTO - inserts new data into a database table
Data Definition Language
(DDL)
Some of the vital DDL statements in SQL are:
* CREATE TABLE - creates a new database table
* ALTER TABLE - alters (changes) a database table
* DROP TABLE - deletes a database table
* CREATE INDEX - creates an index (search key)
* DROP INDEX - deletes an index
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Index
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