1. A computer-based markup serialization method for transferring data contained in an Extensible Markup Language (XML) document into a relational database stored in an electronic storage device having a database management system, for easy subsequent retrieval of data from the database in the XML format and reconstruction of the XML document, the method comprising the steps of: (a) decomposing the XML document according to basic markup types of XML documents' data components; and (b) storing the decomposed XML document in a set of markup tables created in the database, one markup table for each basic markup type.