10.24.1 Problem
You want to classify values into broad categories.
10.24.2 Solution
Use a pattern that is similarly broad.
10.24.3 Discussion
If you need to know only whether values are empty, nonempty, or consist only of certain types of characters, patterns such as the following may suffice:
Pattern |
Type of value the pattern matches |
---|---|
/^$/ |
Empty value |
/./ |
Nonempty value |
/^s*$/ |
Whitespace, possibly empty |
/^s+$/ |
Nonempty whitespace |
/S/ |
Nonempty, and not just whitespace |
/^d+$/ |
Digits only, nonempty |
/^[a-z]+$/i |
Alphabetic characters only (case insensitive), nonempty |
/^w+$/ |
Alphanumeric or underscore characters only, nonempty |
Using the mysql Client Program
Writing MySQL-Based Programs
Record Selection Techniques
Working with Strings
Working with Dates and Times
Sorting Query Results
Generating Summaries
Modifying Tables with ALTER TABLE
Obtaining and Using Metadata
Importing and Exporting Data
Generating and Using Sequences
Using Multiple Tables
Statistical Techniques
Handling Duplicates
Performing Transactions
Introduction to MySQL on the Web
Incorporating Query Resultsinto Web Pages
Processing Web Input with MySQL
Using MySQL-Based Web Session Management
Appendix A. Obtaining MySQL Software
Appendix B. JSP and Tomcat Primer
Appendix C. References