Indexing Technology Research For XML Educational Resource Based On Celts-3 Standard

The popularity of computer and network development has changed the teaching model, in particular, digital learning resources, networking has become an inevitable trend . In this trend, there produces a large number of teaching resources, including not only the traditional physical resources, but also digital resources. Faced with such a large resource pool, management and searching will become quite difficult to. With the issuance of the Standard for Learning Object Metadata, all these teaching resources,which come from different suppliers and has different structure, can be descripted with a unified standard. With the binding of standards and XML, it can greatly improve resource management and the efficiency of retrieval, meanwhile, provide a basis for resource sharing and interoperability.According to the features of the XML educational resources based on the Celts Standard, This proposes an improved index structure to retrieve XML data based on the idea of the numbering scheme ,the inverted list and the path index, so called extended preorder list index. Building index with this index method for XML document according to CELTS-3 standard, we can quickly determine ancestor/ descendant relationships and parent/ child relationships between any pair of nodes in the XML trees ,thus it can efficiently process containment joins in XQuery path expression queries and keyword searches. Also, this paper presents two algorithms for processing structural joins of parent/ child relationship and contain relationship ,which lead to optimal join performance by avoiding scanning on each list joined repeatedly and omitting the examination of elements ,which do not participate in the join ,via index based on parent's information and etc. so it can highly improve the speed of structure join and the efficiency of query execution.