Niklas Tech Blog

Every now and then you need to validate an element or attribute agains multiple patterns.
Say an element is allowed to contain a date both in ‘YYYYnn’ format (where nn is the week number) and ‘seasonYY’ format. To solve this I use the following xsd pattern:

:
   
       
           <xs:pattern value="(19|20[0-9]{2}[0-5][0-9]) | (summer[0-9]{2}) | (winter[0-9]{2}) | (fall[0-9]{2}) | (spring[0-9]{2})"/>
       
   
:

The solution to my problem lies in the ‘|’ and parenthesis. I group the different patterns in parenthesis and separate the patterns with the OR-operator ‘|’. This way I can validate both syntaxes YYYYnn and seasonYY – only one needs to be true

There are of course other ways (shorter) to write the pattern but I choose this way because I believe it is easier to understand.