10. A method for integrating data from one or more XML sources into a single target, the method comprising: applying an XML integration grammar (XIG) to the one or more sources to determine the target, wherein the XIG is generated automatically, the XIG comprising: a set of rules for each production based on a Document Type Definition (DTD) of the target, wherein the production is associated with a parent type and a set of child types, the set of rules comprising: for each child type in the set of child types, a first rule for computing an inherited attribute for the child type by extracting data, via a query, from one or more DTDs corresponding to the one or more XML sources, the query having a query parameter comprising an inherited attribute for the parent type; and for the parent type, a second rule for computing a synthesized attribute for the parent type by grouping synthesized attributes for all child types of the set in the child types; and storing the target.
19. The method of claim 10 , wherein the one or more DTDs includes at least two different DTDs.