Apparatus and method for mapping relational data and metadata to XML

• US 20020099687A1
• Filed: 09/06/2001
• Published: 07/25/2002
• Est. Priority Date: 09/07/2000
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Krishnamurthy, Viswanathan, Murthy, Ravi, Krishnaprasad, Muralidhar, Nimani, Visar
• Granted Patent: US 6,871,204 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/284 Relational databases
• CPC Class Codes: Y10S 707/954 Relational
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

Techniques are provided for mapping XML data and metadata from data in relational databases. According to certain embodiments of the invention, a mechanism is provided to allow the user to use a database query to retrieve data form a relational database in the form of XML documents by canonically mapping object relational data to XML data and canonically mapping object relational schemas to XML-Schemas. The mechanism causes the generation of XML-schema information for the XML documents.

Claims

1. A method of providing data, the method comprising the steps of:

receiving, at a database server, a relational database query to retrieve data that resides in a relational database; and

the database server responding to the relational database query by providing a result of the relational database query from the relational database in a form of one or more XML documents.

2. The method of claim 1, wherein the relational database query specifies which values that answer the relational database query are to be contained in the one or more XML documents, and which other values that answer the relational database query are to be referenced in the one or more XML documents by reference links.

3. The method of claim 1, wherein the step of providing a result to the relational database query in a form of one or more XML documents comprises providing an XML document in which some values that are selected by the relational database query are contained in the XML document and other values that are selected by the relational database query are referenced in the XML document.

4. The method of claim 1 further comprising the step of, during a processing of the relational database query, generating one or more XML-schema that describe features of the one or more XML documents, wherein the features comprise structure of the one or more XML documents.

5. The method of claim 4 further comprising storing at least one of the one or more XML-schema within at least one of the one or more XML documents.

6. The method of claim 1 further comprising the step of, during a processing of the relational database query, generating one or more XML-schema that describe features of the one or more XML documents, wherein the features comprise constraints of the one or more XML documents.

7. The method of claim 4, wherein the one or more XML-schema corresponds to metadata that is associated with the data that is retrieved in response to the relational database query.

8. The method of claim 4, wherein the one or more XML-schema comprises relational database object types from one or more XML namespaces, wherein one or more relational database schemas are mapped to each of the one or more XML namespaces.

9. The method of claim 1, further comprising generating the one or more XML documents, and wherein the step of generating the one or more XML documents comprises using a set of rules that is stored in the relational database to determine how to structure data contained in the one or more XML documents.

10. The method of claim 1, wherein the relational database query selects a plurality of rows in the relational database and wherein the one or more XML documents includes an XML document that aggregates data from the plurality of rows.

11. The method of claim 9, wherein the set of rules comprises rules for mapping a relational database object to a corresponding Database Uniform Resource Indicator reference.

12. The method of claim 9, wherein the set of rules comprises rules for mapping a query language reference to a corresponding Database Uniform Resource Indicator reference.

13. The method of claim 9, wherein the set of rules comprises rules for mapping relational data that is associated with a LOB column to a corresponding Database Uniform Resource Indicator reference.

14. The method of claim 1, wherein the relational database query is satisfied by a plurality of rows and the one or more XML documents includes a single XML document for said plurality of rows.

16. The computer-readable medium of claim 15, wherein the relational database query specifies which values that answer the relational database query are to be contained in the one or more XML documents, and which other values that answer the relational database query are to be referenced in the one or more XML documents by reference links.

17. The computer-readable medium of claim 15, wherein the step of providing a result to the relational database query in a form of one or more XML documents comprises providing an XML document in which some values that are selected by the relational database query are contained in the XML document and other values that are selected by the relational database query are referenced in the XML document.

18. The computer-readable medium of claim 15 further comprising the step of, during a processing of the relational database query, generating one or more XML-schema that describe features of the one or more XML documents, wherein the features comprise structure of the one or more XML documents.

19. The computer-readable medium of claim 18 further comprising storing at least one of the one or more XML-schema within at least one of the one or more XML documents.

20. The computer-readable medium of claim 15 further comprising the step of, during a processing of the relational database query, generating one or more XML-schema that describe features of the one or more XML documents, wherein the features comprise constraints of the one or more XML documents.

21. The computer-readable medium of claim 18, wherein the one or more XML-schema corresponds to metadata that is associated with the data that is retrieved in response to the relational database query.

22. The computer-readable medium of claim 18, wherein the one or more XML-schema comprises relational database object types from one or more XML namespaces, wherein one or more relational database schemas are mapped to each of the one or more XML namespaces.

23. The computer-readable medium of claim 15, further comprising generating the one or more XML documents, and wherein the step of generating the one or more XML documents comprises using a set of rules that is stored in the relational database to determine how to structure data contained in the one or more XML documents.

24. The computer-readable medium of claim 15, wherein the relational database query selects a plurality of rows in the relational database and wherein the one or more XML documents includes an XML document that aggregates data from the plurality of rows.

25. The computer-readable medium of claim 23, wherein the set of rules comprises rules for mapping a relational database object to a corresponding Database Uniform Resource Indicator reference.

26. The computer-readable medium of claim 23, wherein the set of rules comprises rules for mapping a query language reference to a corresponding Database Uniform Resource Indicator reference.

27. The computer-readable medium of claim 23, wherein the set of rules comprises rules for mapping relational data that is associated with a LOB column to a corresponding Database Uniform Resource Indicator reference.

28. The computer-readable medium of claim 15, wherein the relational database query is satisfied by a plurality of rows an d the one or more XML documents includes a single XML document for said plurality of rows.

15. A computer-readable medium carrying one or more sequences of instructions of providing data, which instructions, when executed by one or more processors, cause the one or more processors to carry out the steps:

receiving, at a database server, a relational database query to retrieve data that resides in a relational database; and

the database server responding to the relational database query by providing a result of the relational database query from the relational database in a form of one or more XML documents.