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CHAPTER 36 • INDEXES AND SEARCHINGwww.it-ebooks.infoThe following query would not benefit:SELECT lastname FROM employees WHERE firstname="Ed";To improve this latter query’s performance, you’d need to create separate indexes for the firstnamecolumn.Full-Text IndexesFull-text indexes offer an efficient means for searching text stored in CHAR, VARCHAR, or TEXT datatypes.Before delving into examples, a bit of background regarding MySQL’s special handling of this index is inorder.Because MySQL assumes that full-text searches will be implemented for sifting through largeamounts of natural-language text, it provides a mechanism for retrieving data that produces results thatbest fit the user’s desired result. More specifically, if a user were to search using a string like Apache isthe world's most popular web server, the words is and the should play little or no role in determiningresult relevance. In fact, MySQL splits searchable text into words, by default eliminating any word offewer than four characters. You’ll learn how to modify this behavior later in this section.Creating a full-text index is much like creating indexes of other types. As an example, revisit thebookmarks table created earlier in this chapter, indexing its description column using the full-textvariant:CREATE TABLE bookmarks (id INT UNSIGNED NOT NULL AUTO_INCREMENT,name VARCHAR(75) NOT NULL,url VARCHAR(200) NOT NULL,description MEDIUMTEXT NOT NULL,FULLTEXT(description),PRIMARY KEY(id));In addition to the typical primary index, this example creates a full-text index consisting of thedescription column. For demonstration purposes, Table 36-1 presents the data found in the bookmarks table.Table 36-1. Sample Table Dataid name url description1 Python.org www.python.org The official Python Web site2 MySQL manual http://dev.mysql.com/doc The MySQL reference manual3 Apache site http://httpd.apache.org Includes Apache 2 manual4 PHP: Hypertext www.php.net The official PHP Web site5 Apache Week www.apacheweek.com Offers a dedicated Apache 2 section698