Mapping, indexing and querying of MPEG-7 descriptors in RDBMS with IXMDB

MPEG-7 is a promising standard for the description of multimedia content. A number of applications based on MPEG-7 media descriptions have been set up for research, commercial and industrial applications. Therefore, an efficient storage solution for large amounts of MPEG-7 descriptions is certainly desirable. As a kind of data-centric XML documents, MPEG-7 descriptions can be stored in the relational DBMS for efficient and effective management. The approaches of storing XML data in relational DBMS can be classified into two classes of storage model: schema-conscious and schema-oblivious. The schema-conscious model, however, cannot support complex XPath-based queries efficiently and the schema-oblivious approach lacks the flexibility in typed representation and access. Although the leading database systems have provided functionality for the XML document management, none of them can reach all the critical requirements for the MPEG-7 descriptions management. In this paper, we present a new storage approach, called IXMDB, for MPEG-7 documents storage solution. IXMDB integrates the advantages of both the schema-conscious method and the schema-oblivious method, and avoids the main drawbacks from each method. The design of IXMDB pays attention to both multimedia information exchange and multimedia data manipulation. Its features can reach the most critical requirements for the MPEG-7 documents storage and management. The translation mechanism for converting XQuery to SQL and the support of query from multimedia perspective are provided with IXMDB. Performance studies are conducted by performing a set of queries from the XML perspective and from the multimedia perspective. The experimental results are presented in the paper and initial results are encouraging.