Parent-child query indexing for XML databases
A method for processing queries for a document of elements is provided. The document includes a plurality of subsections where each subsection includes at least a portion of elements in the document. The method comprises: receiving a query for a path of elements in the document of elements; determining a plurality of step queries from the query, each step query including at least a part of the path of elements; for each step query in the plurality of step queries, determining one or more subsections that include elements that correspond to a step query; and determining at least one subsection that includes the path of elements of the query. A result for the query is generated using the at least one subsection.
1. A computer-implemented method of searching a structured document for text having relevance to a given set of terms, using a processor, the method comprising:
receiving a node set corresponding to at least one fragment of the structured document, wherein the fragment includes at least a portion of text of the structured document and at least one corresponding pre-computed step query;
receiving at least one search term;
receiving a pre-computed lookup index with entries corresponding to the fragments, each entry having an associated subtree identifier;
searching the lookup index with the search terms;
returning a set of resulting step queries indicated by the lookup index and corresponding to the search terms;
assessing an intersection of the resulting step queries with the given set of terms, wherein the resulting step queries each have an associated subtree identifier; and
retrieving a node set associated with the intersection and corresponding to a fragment.
2. The method of claim 1 , further comprising post-processing the retrieved step queries to verify that the corresponding set of terms appear contiguously in a corresponding set of subtree fragments.
3. The method of claim 1 , further comprising retrieving a subtree fragment corresponding to a subtree identifier.
4. The method of claim 1 , further comprising performing a post-processing step comprising:
determining that the set of resulting step queries produce a continuous path; and
confirming that the associated full-text terms appear contiguously within the subtrees.
5. The method of claim 1 , wherein each subtree identifier further comprises a relevance score, the relevance score indicating a likelihood of the subtree including a particular target query element, wherein the relevance score is normalized to the number of step queries contained in the associated subtree fragment.
6. The method of claim 5 , wherein the step of retrieving a corresponding fragment is selectively determined according to the relevance score of the associated subtree identifier, wherein a first subtree identifier with a higher relevance score is selected preferentially over an alternate subtree identifier with a lower relevance score.
7. The method of claim 1 , wherein each subtree identifier further comprises a relevance score indicative of a relevance of the subtree to a particular target query element.
8. The method of claim 7 , wherein the relevance score is normalized to the number of step queries contained in the associated subtree fragment.