Call now: 252-767-6166  
Oracle Training Oracle Support Development Oracle Apps

 E-mail Us
 Oracle Articles
New Oracle Articles

 Oracle Training
 Oracle Tips

 Oracle Forum
 Class Catalog

 Remote DBA
 Oracle Tuning
 Emergency 911
 RAC Support
 Apps Support
 Oracle Support

 SQL Tuning

 Oracle UNIX
 Oracle Linux
 Remote s
 Remote plans
 Application Server

 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support

 Remote S


 Consulting Staff
 Consulting Prices
 Help Wanted!


 Oracle Posters
 Oracle Books

 Oracle Scripts

Don Burleson Blog 









Search Engine word stemming and synonym expansion

Oracle Database Tips by Donald Burleson

Today we assume that the search engine can locate all of the matching pages (precision) and return relevant results.  Google, considered the de-facto engine by many technies has rocketed Google into a billion dollar industry, with over a dozens contenders (Magellan, Alta Vista, MSN, Mama, Etc) ripping at Google's heels.

From an academic perspective, the "best" search engine is the one that returns the "right" answer, the one that derived the "meaning" of the query and returned on-point results.  Old research attempted to qualify the quality of search engines using difficult metrics such as Search Engine Precision and Recall.

A central part of quantifying the "relevance" of any query is to "expand" the query into a more complex query.  For example, consider the query:

     cheap condo Los Angeles no credit check

Word Stemming

"Word stemming" is defined as the ability to include word variations.  For example any noun-word would include variations (whose importance is directly proportional to the degree of variation) With word stemming, we use quantified methods for the rules of grammar to add word stems and rank them according to their degree of separation from the root word.  For example, we might see stems identified for "cheap", "condo" and "check":

(cheap or cheaper)
(condo and condos)
(check and checked and checking)

Synonym Expansion

Synonym Expansion is where we take variants of the word and assign them to the search engine query.  Retuning to our example, the term "cheap" might indicate that the searcher is also interested in similar terms for a low cost:

"low cost"

Similarly, the term "condo" might indicate that the searcher is also interested in similar types on housing"

"rental property"

When we expand a query we develop a complex word search expression for the base engine.  In our case the simple "cheap condo Los Angeles no credit check" is transformed into a far more complex Boolean form:

(cheap or cheaper)
(condo and condos)
(check and checked and checking)
(cheaper or inexpensive or "low cost" or bargain)
(condo or apartment or flat or "rental property")

Oh,  but what about adding stems of the synonyms:

(apartment or apartments)
(bargains or bargain or bargaining)


Of course, we have not yet assigned weights to the synonyms in the query.  For example the word "flat" is an obscure term for housing and it would have far less weight than the original "condo".

If you like Oracle tuning, you may enjoy my new book "Oracle Tuning: The Definitive Reference", over 900 pages of my favorite tuning tips & scripts. 

You can buy it direct from the publisher for 30%-off and get instant access to the code depot of Oracle tuning scripts.



Oracle Training at Sea
oracle dba poster

Follow us on Twitter 
Oracle performance tuning software 
Oracle Linux poster


Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.  Feel free to ask questions on our Oracle forum.

Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.

Errata?  Oracle technology is changing and we strive to update our BC Oracle support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:  

and include the URL for the page.


Burleson Consulting

The Oracle of Database Support

Oracle Performance Tuning

Remote DBA Services


Copyright © 1996 -  2020

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.