eXtropia: the open web technology company
Technology | Support | Tutorials | Development | About Us | Users | Contact Us
 ::   Tutorials
 ::   Presentations
Perl & CGI tutorials
 ::   Intro to Perl/CGI and HTML Forms
 ::   Intro to Windows Perl
 ::   Intro to Perl 5
 ::   Intro to Perl
 ::   Intro to Perl Taint mode
 ::   Sherlock Holmes and the Case of the Broken CGI Script
 ::   Writing COM Components in Perl

Java tutorials
 ::   Intro to Java
 ::   Cross Browser Java

Misc technical tutorials
 ::   Intro to The Web Application Development Environment
 ::   Introduction to XML
 ::   Intro to Web Design
 ::   Intro to Web Security
 ::   Databases for Web Developers
 ::   UNIX for Web Developers
 ::   Intro to Adobe Photoshop
 ::   Web Programming 101
 ::   Introduction to Microsoft DNA

Misc non-technical tutorials
 ::   Misc Technopreneurship Docs
 ::   What is a Webmaster?
 ::   What is the open source business model?
 ::   Technical writing
 ::   Small and mid-sized businesses on the Web

Offsite tutorials
 ::   ISAPI Perl Primer
 ::   Serving up web server basics
 ::   Introduction to Java (Parts 1 and 2) in Slovak


Introduction to Databases for Web Developers
Basics of an SQL Query  
As we have already alluded to, a "query" is a structured request to the database for data. At its core, a query is something like, "Hey, give me a list of all the clients in the CLIENTS table who live in the 213 area code!"

Or, in more specific terms, a query is a simple statement (like a sentence) which requests data from the database.

Much as is the case with English, an SQL statement is made up of subjects, verbs, clauses, and predicates.

Let's take a look at the statement made above. In this case, the subject is "hey you database thing". The verb is "give me a list". The clause is "from the CLIENTS table". Finally, the predicate is "who live in the 213 area code."

We'll explain the code later, but let me show you what the above statement might look like in SQL:


SELECT = VERB = give me a list
area_code = 213 = PREDICATE = who live in the 213 area code

Previous | Next | Table of Contents