Regular expression for validating special characters
Also, you want to include the start and end of string placemarkers ^ and $ Update: As elclanrs understood (and the rest of us didn't, initially), the [\w] is the same as [a-z A-Z0-9_] Though the dash doesn't need escaping when it's at the start or end of the list, I prefer to do it in case other characters are added.
Additionally, the means you need at least one of the listed characters.
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In Oracle Database 10g, you can use both SQL and PL/SQL to implement regular expression support.