Designing and Querying a Compact Redundancy Free XML Storage

ABSTRACT

XML, the universal data format for data exchange has seen phenomenal increase in database size necessitating the need for its compact storage coupled with simple accessibility. In previous works, all XML databases are implemented as a tree based structure which leads to increased space complexity. The proposed structure called RFX (Redundancy Free XML storage structure), addresses this issue by using a non tree based structure. This unique blend of hierarchical and relational databases in a single structure is largely effective in saving storage space thus achieving an increased compaction. Further RFX conceptualizes the separation of the information in the entire database as the topology layer, the tag layer and the data layer. The RFX structure has been designed to accommodate multiple document types i.e. Containment, Intra and Inter types of XML documents. Moreover in this proposal, it is ensured that the relationships among documents are never disturbed and are seamless with respect to their original counterparts. The document is parsed and stored in a different form to permit simple accessibility which is largely effective while querying and maintaining documents involving one-to-many relationships. Thus RFX paves way to effectively query and maintain the XML databases along with substantial compaction. This approach shows that the proposed RFX structure is space efficient, redundant free, and time efficient to update and to query Single, Intra and Inter structured XML document. The effectiveness of the approach makes it suitable for memory limited devices such as PDA. Performance evaluation over variety of XML documents and the user queries conform to the same.