Many Objections to DTDs
- Syntax is not XML
- unique (some say bizarre)
- requires single-purpose processor (XML parser)
- Restricted modeling functions
- No context-dependent models
- No AND functionality
- No element data typing (therefore no type validation)
- No inheritance (except by convention xml:lang)
- Documentation only as comments
- Lacks other things RDBMS schemas provide: referential integrity, co-occurrence
constraints, classing and derivation
