An XML schema is compiled into an annotated automaton encoding, which includes a parsing table for structural information and annotation for type information. The representation is extended to include a mapping from schema types to states in a parsing table. To validate a fragment against a schema type, it is necessary simply to determine the state corresponding to the schema type, and start the validation process from that state. When the process returns to the state, fragment validation has reached successful completion. This approach is more efficient than a general tree representation. Only the data representation of the schema information is handled, making it much easier than manipulating validation parser code generated by a parser generator. In addition, only one representation is needed for schema information for both document and fragment validation. This approach also provides a basis for incremental validation after update.