Normalization design of XML database schema for eliminating redundant schemas and satisfying lossless join

Normalization design of XML database schema is to produce a set of XML schemas or DTDs that can well represent data dependencies and eliminate redundancies. In the current researches on normalization design of XML database schema, redundancies in XML database schema are not studied specially and classified, and normalization design algorithms are only converting an initial schema into one in one of normal forms proposed in these researches. The paper defines hierarchical schema representing XML database schema and corresponding normal forms first normal form (INF) and second normal form (2NF)for XML database schema, and presents the algorithm eliminating redundant schemas and normalization design algorithm for 2NF. In XML database schema in INF, the set of full and embedded MVDs are implied by the given set of MVDs. XML database schema in 2NF satisfies properties for INF, eliminates redundant schemas, and satisfies lossless join property.