Require to validate the xml

Question

I have two requirements:
1. to Validate the xml to follow a predefined structure - this is done.
2. to validate the xml on basis of some conditions - this is to be done.
To eleborate, suppose i have a xml structure such as:
<books>
  <book>
      <author name = "abc" publisher="xyz"/>
      <title>something</title>
       <price>$2</price>
  </book>
  <book>
     <author name = "cde" publisher="uvw"/>
      <title>otherthing </title>
       <price>$2</price>
  </book>
</books>these data are to be uploaded to the database but before uploading the database i want to perform some validations on the data for ex. if the author name is "abc", then the publisher can only be "xyz".
Any idea how the validation on the data inside the can be performed.

Answer 1

Use a validating parser (any recent Xerces, for one) and switch on the validation feature. Very much vendor-specific, so look at the docs of your parser. Oh, you do have a schema for these documents, don't you?