Hi all I'm trying all the time to make a regular expression for XML in my .xsd.
This expression should verify an ISBN-13 number but I couldn't get further than this:
ISBN (978|979)[ |-][0-9]{1,5}[ |-][0-9]{1,7}[ |-][0-9]{1,7}[0-9]{1}
This is ok if somebody fills in a correct ISBN13, but it is also still possible to make ISBNs which are much longer (for example it is still possible to make the first block of numbers 5 long and the second 7 digits and the third also 7 digits long).
I am very new to this topic and I cannot solve this problem, therefore I hope somebody could help me or solve my problem.
I know what an ISBN 13 consists of, I checked wikipedia and other websites, but my actual problem is the regular expression it self.
I hope that this wasnt asked earlier, so I am sorry if somebody asked this question earlier. jajay07