EXPRESSING AND EXECUTING SEMANTIC QUERIES WITHIN A RELATIONAL DATABASE

• US 20120226710A1
• Filed: 05/15/2012
• Published: 09/06/2012
• Est. Priority Date: 02/16/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bowers, Stuart M., Jackson, Thomas E., Karkanias, Chris Demetrios, Brown, Allen L., Campbell, David G., Aust, Brian S.
• Granted Patent: US 9,275,146 B2
• Time in Patent Office: Days
• US Class Current: 707/769
• CPC Class Codes: G06F 16/20 of structured data, e.g. relational data
• CPC Class Codes: G06F 16/2228 Indexing structures
• CPC Class Codes: G06F 16/243 Natural language query formulation
• CPC Class Codes: G06F 16/2455 Query execution
• CPC Class Codes: G06F 16/284 Relational databases
• CPC Class Codes: G06F 16/951 Indexing; Web crawling techniques

Abstract

Semantic queries are expressed and executed within a relational database. This can be done by defining semantic rules applied to execute the semantic queries using table valued functions and common table expressions, and then simply calling the defined table valued functions to execute the queries.

Claims

1. A computer-implemented method of generating a semantic query, comprising:

receiving a query at a relational database;

identifying the query as a semantic query;

determining whether the semantic query can be directly expressed within the relational database;

if so, generating a table valued function representing the semantic query within the relational database; and

if not, providing the semantic query to a semantic processing engine for processing.

2. The computer-implemented method of claim 1 wherein identifying the query as a semantic query comprises:

determining that the query depends, for its application, on application of a semantic rule.

3. The computer-implemented method of claim 2 wherein generating a table valued function comprises:

generating the table valued function with a common table expression to represent the semantic rule.

4. The computer-implemented method of claim 3 and further comprising:

processing the semantic query within the relational database by calling the table valued function.

5. The computer-implemented method of claim 4 wherein processing the semantic query comprises:

performing temporary tabling within the relational database, using the common table expression, to generate bindings within the relational database, without materializing the bindings an a memory external to the relational database.

6. The computer-implemented method of claim 2 wherein generating the table valued function comprises:

defining edges and paths in a data tree structure stored in the relational database that correspond to values that are examined and returned from the table valued function.

7. The computer-implemented method of claim 6 wherein one of the paths include a first path that defines a current path under consideration within the tree structure, the current path starting at a subject node and ending at an object node.

8. The computer-implemented method of claim 7 wherein the edges define new edges, not yet considered in the tree structure in the relational database, each edge starting at a subject node and ending at an object node.

9. The computer-implemented method of claim 8 wherein generating a table valued function comprises:

generating the table valued function so an object node of the first path comprises a subject node for a next edge to be considered.

10. The computer-implemented method of claim 8 wherein generating a table valued function comprises:

generating a plurality of different table valued functions to accommodate different bindings of the subject nodes and object nodes.

11. The computer-implemented method of claim 10 wherein generating a plurality of different table valued functions comprises:

generating a first table valued function to represent the semantic query and to define binding only subject nodes to a given value.

12. The computer-implemented method of claim 11 wherein generating a plurality of different table valued functions comprises:

generating a second table valued function to represent the semantic query and to define binding only object nodes to a given value.

13. The computer-implemented method of claim 12 wherein generating a plurality of different table valued functions comprises:

generating a third table valued function to represent the semantic query and to define binding both subject nodes and object nodes to given values.

14. The computer-implemented method of claim 13 wherein generating a plurality of different table valued functions comprises:

generating a fourth table valued function to represent the semantic query and to define binding neither subject nodes nor object nodes to given values.

15. A computer-implemented method of processing a semantic query, comprising:

receiving a query at a relational database;

identifying the query as a semantic query;

determining whether the semantic query can be directly expressed within the relational database;

if so;

generating a table valued function with a common table expression representing the semantic query within the relational database; and

processing the semantic query by performing temporary tabling within the relational database, using the common table expression, to generate bindings within the relational database, without materializing the bindings in a memory external to the relational database; and

if not, providing the semantic query to a semantic processing engine for processing.

16. The computer-implemented method of claim 15 wherein identifying the query as a semantic query comprises:

determining that the query depends, for its application, on application of a semantic rule.

17. The computer-implemented method of claim 16 wherein generating a table valued function comprises:

generating the table valued function with the common table expression to represent the semantic rule.

18. A computer-implemented method of retrieving data from a relational database having a processing component and a relational data store, comprising:

receiving a semantic query that depends, for its execution, on application of at least one semantic rule;

expressing the semantic query within the relational database, using the processing component, wherein expressing the semantic query further comprises generating a table valued function that defines a semantic rule to be called in executing the semantic query;

executing the semantic query against the relational data store, using the processing component within the relational database, wherein executing the semantic query further comprises calling the table valued function; and

returning database results, using the processing component, generated from execution of the semantic query.

19. The computer-implemented method of claim 18 wherein the semantic query comprises a recursive semantic query requiring application of a recursive semantic rule and wherein generating a table valued function comprises:

generating the table valued function using a common table expression to express the recursive semantic rule.

20. The computer-implemented method of claim 18 wherein the semantic query comprises a bifurcating recursive semantic query requiring application of a bifurcating recursive semantic rule and wherein expressing comprises:

generating a table valued function that defines the bifurcating recursive semantic rule.