What is SQL

Part of the You Can Learn SQL series.
By Ken Brown
Editor, YouCanLearnSeries.com
August 31, 2004

SQL is Structured Query Language. A language specifically designed to work with data that resides in relational databases.

SQL is not a procedural language. You wouldn’t use it like you would a language like Visual Basic or C++. SQL is a language built on using set theory on records. You ask the database what you want using SQL and the database returns a result set in its most optimized way based on the question you asked.

SQL does more than work with data. You can create databases, alter databases, drop different objects in the database. There are SQL tools to add new data to a database and retrieve information from the database. The reason SQL was developed was to work with relational databases.

SQL has three command languages to help it manage the database and its objects and to handle data.
1. DCL – Data Control Language
2. DML – Data Manipulation Language
3. DDL – Data Definition Language

The Data Control Language has tools to protect the database from harm. The commands of the DCL are COMMIT, ROLLBACK, GRANT and REVOKE. These help prevent accidental deletion of records from the database.

The Data Manipulation Language contains the statements that retrieve and maintain the data found in a database table. The commands are SELECT, INSERT, DELETE and UPDATE.

The Data Definition Language is used for defining database objects. The commands are CREATE, ALTER and DROP and can be used on a variety of objects in a database.

There are also reserved words and specific data types that are available.

In review, with SQL the whole idea is to collect a set of records that match the criteria you specify and then perform some operation on those records. It is also used to create a database and the objects that are necessary to support the database.

Home| About Us | NewsLetters | Contact Us |

Copyright © 2004-2014 You Can Learn Series

You Can Learn Series Home Page You Can Learn Series
You Can Learn Series Home Page Home            About the creators of YouCanLearnSeriesAbout Us      Contact YouCanLearnSeriesContact Us      Site map of YouCanLearnSeriesSite Map      Privacy Policy of You Can Learn SeriesPrivacy Policy       Terms of Use of You Can Learn Series web siteTerms of Use       YouCanLearnSeries RSS feed for SQL tips and tutorials     
C# and ASP.Net Programming TipsC# and ASP.Net      SQL Tutorial, tips and tricks for DBA'sSQL       Landscaping Tips for Home GardenersLandscaping       WeightLifting Tips for the Young and OldWeightLifting       Good health TipsGoodHealth       Learn about Great Travel DestinationsTravel     Web Business TipsWeb Business     

You Can Learn C# and ASP.Net SeriesC# and ASP.Net

You Can Learn SQL SeriesSQL
  Data Definition LanguageData Definition Language
  Data Manipulation LanguageData Manipulation Language
  What is a DatabaseWhat is a Database
  What is SQLWhat is SQL
  SELECT StatementSELECT Statement
  INSERT StatementINSERT Statement
  DELETE StatementDELETE Statement
  UPDATE StatementUPDATE Statement

You Can Learn Landscaping and Gardening SeriesLandscape Tips
You Can Learn WeightLifting SeriesWeightLift Tips
You Can Learn Good Health SeriesGood Health Tips
You Can Learn Series NewslettersNewsletters
Learn about Great Travel DestinationsTravel
You Can Learn Series Web Business TipsWeb Business Tips

Bill Welter - The Prepared Mind of a Leader

Americas Public Schools