1. A computer program product, comprising: a computer readable storage device to store a computer readable program, wherein the computer readable program, when executed by a processor within a computer, causes the computer to perform operations for simplifying an extensible markup language (XML) schema, the operations comprising: identifying data in an instance specification as variable data and fixed data, wherein the instance specification corresponds to a complex XML schema; determining a set of types comprising the variable data, wherein the set of types conforms to a structure of the complex XML schema; capturing the set of types as metadata annotations associated with the instance specification; generating a simplified XML schema for the instance specification using the set of types; and extracting an instance of the simplified XML schema from an instance of the complex XML schema based on mapping information corresponding to the instance specification and a heuristic for existing instances of the complex XML schema.