[This may be a FAQ, in which case I apologize in advance. I have searched the list archives, but not the forums, for postings related to this issue.] It seems that oXygen's XML validator does not know how to properly apply multiple 'pattern' facets when validating against a RelaxNG grammar. To my knowledge, multiple occurrences of a 'pattern' facet are allowed on xsd: datatypes; the content in the instance should match all of the patterns specified in order to be considered valid. When several <param> elements are included, all the constraints must be met (in other words, the result is a logical "and" of all the conditions). Also note that the same facet can't be repeated twice except for the facet named 'pattern'. -- van der Vlist, Eric. _RELAX_NG_, Ch 8 sect. "Facets", p. 93 However, oXygen's internal validator (xerces, right?) seems to use "or" instead of "and". Here is a test. --------- begin t.rnc --------- datatypes xsd = "http://www.w3.org/2001/XMLSchema-datatypes" start = element test { element alpha { xsd:token { pattern = "a{1,9}B{3}c" pattern = "a{3}B{1,9}c" maxLength = "25" } }+ } --------- end t.rnc --------- --------- begin t.xml --------- <?xml version="1.0" encoding="UTF-8"?> <?oxygen RNGSchema="file:/private/tmp/t.rnc" type="compact"?> <test> <alpha>aaaBBBc</alpha> <alpha>aBBBc</alpha> <alpha>aaaBc</alpha> </test> --------- end t.xml --------- I expect the above file to be invalid: line 6 fails to match the first xsd pattern in the schema and line 5 fails to match the second. I expect line 4 to be valid. I ran xmllint, jing, and rnv on the command-line, and they all flag lines 5 & 6 as invalid (i.e., they agree with me.) I don't know how to run xerces from the command-line. (Feel free to tell me ... :-) But oXygen says t.xml is valid (both the "live" validation that occurs while I type and the "static" validation that occurs with CMD-shift-V say it is valid).