Regular Expressions

Regular expression support for pattern matching was introduced in Oracle 10g. It offers a powerful alternative to older, less robust pattern matching features such as the LIKE operator. Oracle regular expression support is based on the POSIX standard, but it also has some non-POSIX extensions similar to those used in the PERL programming language.

In the first four tutorials the Oracle conditions and functions that support regular expressions will be introduced. Since all Oracle regular expression features recognize the same regular expression patterns, these four tutorials will not attempt to explore regular expression syntax in detail. This will be done in the remaining tutorials which discuss four different aspects of regular expression pattern matching.

  1. WHAT single piece of text are we trying to match?
  2. HOW MANY repetitions of that text are we trying to match?
  3. WHERE in the source string should we look for a match?
  4. WHICH occurrence of the text do we want to match?



Reprinted from xkcd.com - Regular Expressions with permission.





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