Define an element as non-empty in RelaxNG
问题 I've started using RelaxNG to specify XML message schemas, and using PHP DOMDocument to validate and parse incoming messages, but can't figure out how to define a text node so that it cannot be empty. Example schema: <?xml version="1.0"?> <element name="amhAPI" xmlns="http://relaxng.org/ns/structure/1.0"> <element name="auth"> <element name="validateUser"> <element name="username"> <text/> </element> <element name="password"> <text/> </element> </element> </element> </element> However, the