Formal XML document validation (based on an XML Schema Definition) is often confusing. The schema says one thing, and the document instance says another, but the tool you are using doesn’t seem to interpret things correctly (?!@#?).
Sometimes the problem is in the interpretation of “invalid”……..and deciphering the XML standard and how vendors implement it will make your head spin. When you have time, go thru the w3c site (www.w3c.org). It’s a great site, but you will need to spend lots of time there to understand all the nuances of xml and its parsing.
What is probably more important is that you know all the ways that you can quickly test validation to better understand your documents and the situation you are currently dealing with…. I usually just google “xml validation” to find the myriad of sites available, but found one this morning that has a really elegant interface and thought I’d mention it here.
Like many online validation sites, quick validation is offered for free as an attraction to come to the site and see what other xml tools are available. I will be certainly be browsing this site further and looking at their other tools because their validation tooling was so easy to use:
When you go there you will see a dialog that lets you browse for a local document and then also browse for its xsd. You then get formal xsd validation results that tell you whether the document is invalid or not, and show you any errors produced by the parser.
Keep this url handy when you need to quickly check a document against its xsd and better understand the behavior of the tool you are using to manipulate it.