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Sunday, 25 December 2011

What is HTML?

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HTML is a language for describing web pages.
  • HTML stands for Hyper Text Markup Language
  • HTML is not a programming language, it is a markup language
  • A markup language is a set of markup tags
  • HTML uses markup tags to describe web pages 

HTML Tags
HTML markup tags are usually called HTML tags
  • HTML tags are keywords surrounded by angle brackets like <html>
  • HTML tags normally come in pairs like <b> and </b>
  • The first tag in a pair is the start tag, the second tag is the end tag
  • Start and end tags are also called opening tags and closing tags

HTML Documents = Web Pages
  • HTML documents describe web pages
  • HTML documents contain HTML tags and plain text
  • HTML documents are also called web pages
Know more about HTML Tags : http://www.indiastudychannel.com/resources/145204-How-use-HTML-tags.aspx 

What is SQL DML and DDL?

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SQL can be divided into two parts: The Data Manipulation Language (DML) and the Data Definition Language (DDL).
The query and update commands form the DML part of SQL:
  • SELECT - extracts data from a database
  • UPDATE - updates data in a database
  • DELETE - deletes data from a database
  • INSERT INTO - inserts new data into a database
The DDL part of SQL permits database tables to be created or deleted. It also defines indexes (keys), specify links between tables, and impose constraints between tables. The most important DDL statements in SQL are:
  • CREATE DATABASE - creates a new database
  • ALTER DATABASE - modifies a database
  • CREATE TABLE - creates a new table
  • ALTER TABLE - modifies a table
  • DROP TABLE - deletes a table
  • CREATE INDEX - creates an index (search key)
  • DROP INDEX - deletes an index