query translation scheme for heterogeneous xml data sources
In order to formulate a meaningful XML query, a user must have some knowledge of the schema of the XML documents to be queried. The query will succeed only if the schema of the actual documents is consistent with the user's information. When a user queries a collection of documents collected from heterogeneous XML data sources, there is a high possibility that these documents do not all conform to the same schema assumed by the user, thus causing the query to fail. In this paper, we try to solve this query and data schema mismatching problem by proposing a query translation scheme. Without attempting to solve the general problem of schema integration, we present an inclusion mapping algorithm that decides how compatible the schema of the query and the schema of the target XML documents are. Based upon the compatibility, the query will be executed directly, or translated according to the target schema and then executed, or rejected.
xml heterogeneous databases