A native XML database supporting approximate match search

XML is becoming the standard representation format for metadata. Metadata for multimedia documents, as for instance MPEG-7, require approximate match search functionalities to be supported in addition to exact match search. As an example, consider image search performed by usingMPEG-7 visual descriptors. It does not make sense to search for images that are exactly equal to a query image. Rather, images similar to a query image are more likely to be searched. We present the architecture of an XML search engine where special techniques are used to integrate approximate and exact match search functionalities.