Extensible RDF databases

• US 8,489,649 B2
• Filed: 12/13/2010
• Issued: 07/16/2013
• Est. Priority Date: 12/13/2010
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Yalamanchi, Aravind, Perry, Matthew
• Primary Examiner(s): Vital, Pierre
• Assistant Examiner(s): Mitiku, Berhanu
• Application Number:
  US12/966,899
• Publication Number:
  US 20120150922A1
• Time in Patent Office: 946 Days
• Field of Search: None
• US Class Current: 707/809
• CPC Class Codes: G06F 16/22 Indexing; Data structures therefor; Storage structures
• CPC Class Codes: G06F 16/24564 Applying rules; Deductive queries

Abstract

A method and apparatus for introducing domain-specific data types with associated semantics in an RDF database system using an extensibility framework mechanism. The extensibility framework mechanism allows users to map serialized instance data for a particular user-defined data type to properties of a base data structure associated with the domain-specific data and to map instance data in base data structures to the data'"'"'s serialized form. The RDF database system may return inferred properties of RDF data stored in domain-specific data types in response to a query on the data. Further, the RDF database system may infer relationships between resources in stored data.

Claims

1. A computer-executed method comprising:

a database management system receiving, from a user, definition information for a definition of a new database data type;

wherein the definition information includes a first mapping between one or more attributes of the new database data type and one or more attributes of a particular base data structure of the database management system;

wherein the definition information includes a second mapping between one or more attributes of the particular base data structure of the database management system and one or more attributes of the new database data type;

storing, in an instance of the particular base data structure of the database management system, a particular subject-predicate-object expression that comprises a particular data associated with the new database data type;

wherein each subject-predicate-object expression corresponds to a subject, a predicate, and an object;

wherein a predicate describes a first relationship between a corresponding subject and object;

wherein the step of storing further comprises;

identifying the particular subject-predicate-object expression as including the particular data associated with the new database data type;

in response to identifying the particular subject-predicate-object expression, extracting, based on the first mapping, a value of a particular attribute from the particular data of the particular subject-predicate-object expression; and

based on the first mapping, storing the value of the particular attribute in the instance of the particular base data structure;

receiving a request for at least a portion of the particular data of the particular subject-predicate-object expression;

in response to receiving the request, identifying the instance of the particular base data structure;

based on the second mapping, reconstructing the at least a portion of the particular data of the particular subject-predicate-object expression from the instance of the particular base data structure; and

returning the reconstructed at least a portion of the particular data in response to the request;

wherein the method is performed by one or more computing devices.

2. The computer-executed method of claim 1, wherein:

a subject-predicate-object expression is organized as a directed, labeled graph; and

the subject and object are nodes and the predicate is an edge.

3. The computer-executed method of claim 1, wherein a subject-predicate-object expression is formatted according to Resource Description Framework (RDF).

4. The computer-executed method of claim 1, wherein the definition information is formatted according to RDF.

5. The computer-executed method of claim 1, wherein the new database data type is associated with a set of rules for inferring data, and wherein a particular rule in the set of rules for inferring data reflects a third mapping between the particular attribute and a second attribute of the new database data type, wherein a value for the second attribute is not stored at said instance of the particular base data structure, the method further comprising:

receiving a first query on the database management system that includes a reference to the second attribute;

in response to receiving the first query, writing a second query that infers the value for the second attribute based on the third mapping;

evaluating the second query to produce a query response; and

returning the query response in response to the first query.

6. The computer-executed method of claim 1, wherein the new database data type is associated with a set of rules for inferring data, the method further comprising:

receiving a first query on the database management system that includes a reference to a second relationship for a first resource referred to in the particular subject-predicate-object expression;

in response to receiving the first query, writing a second query that selects a second resource for the second relationship based, at least in part, on one or more rules of the set of rules for inferring data and one of;

a value for at least a portion of the particular data, and

a second subject-predicate-object expression stored in storage for the database management system;

evaluating the second query to produce a query response; and

returning the query response in response to the first query.

7. The computer-executed method of claim 6, wherein:

the set of rules for inferring data includes a plurality of rules for determining a resource for the second relationship; and

the step of writing further comprises writing the second query to select resources based on each rule of the plurality of rules.

8. The computer-executed method of claim 1, wherein:

the particular data is formatted as serialized, structured text;

the first mapping includes a location identifier that identifies the particular attribute in the particular data; and

the first mapping comprises a second attribute of the particular base data structure that corresponds with the particular attribute.

17. The computer-executed method of claim 1, wherein the particular base data structure is implemented through an extensibility framework mechanism for the database management system.

18. The computer-executed method of claim 1, wherein:

the request for at least a portion of the particular data of the particular subject-predicate-object expression is a request for the particular subject-predicate-object expression;

reconstructing the at least a portion of the particular data of the particular subject-predicate-object expression from the instance of the particular base data structure further comprises reconstructing the particular subject-predicate-object expression based, at least in part, on the instance of the particular base data structure and on the second mapping; and

returning the reconstructed at least a portion of the particular data in response to the request further comprises returning the reconstructed particular subject-predicate-object expression as a response to the request.

19. The computer-executed method of claim 18, wherein reconstructing the particular subject-predicate-object expression further comprises placing a value of a particular attribute of said one or more attributes included in the second mapping for the particular base data structure at a location, in the reconstructed particular subject-predicate-object expression, identified by a path expression associated with a certain attribute, of the one or more attributes included in the second mapping for the new database data type, in the definition information.

9. A non-transitory computer-readable storage medium that stores instructions which, when executed by one or more processors, cause:

a database management system receiving, from a user, definition information for a definition of a new database data type;

wherein the definition information includes a first mapping between one or more attributes of the new database data type and one or more attributes of a particular base data structure of the database management system;

wherein the definition information includes a second mapping between one or more attributes of the particular base data structure of the database management system and the one or more attributes of the new database data type;

storing, in an instance of the particular base data structure of the database management system, a particular subject-predicate-object expression that comprises a particular data associated with the new database data type;

wherein each subject-predicate-object expression corresponds to a subject, a predicate, and an object;

wherein a predicate describes a first relationship between a corresponding subject and object;

wherein the step of storing further comprises;

identifying the particular subject-predicate-object expression as including the particular data associated with the new database data type;

in response to identifying the particular subject-predicate-object expression, extracting, based on the first mapping, a value of a particular attribute from the particular data of the particular subject-predicate-object expression; and

based on the first mapping, storing the value of the particular attribute in the instance of the particular base data structure;

receiving a request for at least a portion of the particular data of the particular subject-predicate-object expression;

in response to receiving the request, identifying the instance of the particular base data structure;

based on the second mapping, reconstructing the at least a portion of the particular data of the particular subject-predicate-object expression from the instance of the particular base data structure; and

returning the reconstructed at least a portion of the particular data in response to the request.

10. The non-transitory computer-readable storage medium of claim 9, wherein:

a subject-predicate-object expression is organized as a directed, labeled graph; and

the subject and object are nodes and the predicate is an edge.

11. The non-transitory computer-readable storage medium of claim 9, wherein a subject-predicate-object expression is formatted according to Resource Description Framework (RDF).

12. The non-transitory computer-readable storage medium of claim 9, wherein the definition information is formatted according to RDF.

13. The non-transitory computer-readable storage medium of claim 9, wherein the new database data type is associated with a set of rules for inferring data, and wherein a particular rule in the set of rules for inferring data reflects a third mapping between the particular attribute and a second attribute of the new database data type, wherein a value for the second attribute is not stored at said instance of the particular base data structure, further comprising instructions for:

receiving a first query on the database management system that includes a reference to the second attribute;

in response to receiving the first query, writing a second query that infers the value for the second attribute based on the third mapping;

evaluating the second query to produce a query response; and

returning the query response in response to the first query.

14. The non-transitory computer-readable storage medium of claim 9, wherein the new database data type is associated with a set of rules for inferring data, further comprising instructions for:

receiving a first query on the database management system that includes a reference to a second relationship for a first resource referred to in the particular subject-predicate-object expression;

in response to receiving the first query, writing a second query that selects a second resource for the second relationship based, at least in part, on one or more rules of the set of rules for inferring data and one of;

a value for at least a portion of the particular data, and

a second subject-predicate-object expression stored in storage for the database management system;

evaluating the second query to produce a query response; and

returning the query response in response to the first query.

15. The non-transitory computer-readable storage medium of claim 14, wherein:

the set of rules for inferring data includes a plurality of rules for determining a resource for the second relationship; and

the step of writing further comprises writing the second query to select resources based on each rule of the plurality of rules.

16. The non-transitory computer-readable storage medium of claim 9, wherein:

the particular data is formatted as serialized, structured text;

the first mapping includes a location identifier that identifies the particular attribute in the particular data; and

the first mapping comprises a second attribute of the particular base data structure that corresponds with the particular attribute.

20. The non-transitory computer-readable storage medium of claim 9, wherein the particular base data structure is implemented through an extensibility framework mechanism for the database management system.

21. The non-transitory computer-readable storage medium of claim 9, wherein:

the request for at least a portion of the particular data of the particular subject-predicate-object expression is a request for the particular subject-predicate-object expression;

reconstructing the at least a portion of the particular data of the particular subject-predicate-object expression from the instance of the particular base data structure further comprises reconstructing the particular subject-predicate-object expression based, at least in part, on the instance of the particular base data structure and on the second mapping; and

returning the reconstructed at least a portion of the particular data in response to the request further comprises returning the reconstructed particular subject-predicate-object expression as a response to the request.

22. The non-transitory computer-readable storage medium of claim 21, wherein reconstructing the particular subject-predicate-object expression further comprises placing a value of a particular attribute of said one or more attributes included in the second mapping for the particular base data structure at a location, in the reconstructed particular subject-predicate-object expression, identified by a path expression associated with a certain attribute, of the one or more attributes included in the second mapping for the new database data type, in the definition information.