Looking at mapping, indexing & querying of MPEG-7 descriptors in RDBMS with SM3

Abstract

MPEG-7 documents, which are primarily for multimedia information exchange, are also data-centric XML documents. Due to its advantages, the relational DBMS is the best choice for storing such XML documents. Storing XML data in relational DBMS can be classified into two classes of storage model: structure-mapping and model-mapping. However, the structure-mapping model cannot support complex Xpath-based query efficiently and model mapping approach lacks the flexible capability in representing all kinds of datatypes. In this paper, we present a new storage approach, called SM3. As an XML document, MPEG-7 document can be viewed as XML tree. Such a tree graph, where the internal nodes are element type with element contents, represents the structure of document and can be viewed as nodes which are meaningful only for document traversal. The leaf node, which is a single-valued attribute or element type with text content, has little usage for XML tree routing as it is the end-point of Xpath. So it can be viewed as the special node which only holds value. In this paper, SM3 was designed to use model-mapping approach to store all internal nodes and structure-mapping model to store all leaf nodes. SM3 integrate the advantages of those two models and avoid the main drawbacks from each method. Performance studies are conducted by comparing SM3 with XParent (a pure model-mapping method) and SM3 with XML-DBMS (a pure structure-mapping method). The experimental results are presented in the paper and initial results are encouraging.