Techniques of efficient XML meta-data query using XML table index

• US 20070239681A1
• Filed: 03/31/2006
• Published: 10/11/2007
• Est. Priority Date: 03/31/2006
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Arora, Vikas, Liu, Zhen, Kotsovolos, Susan, Krishnaprasad, Muralidhar, Chang, Hui
• Granted Patent: US 7,644,066 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/81 Indexing, e.g. XML tags; Data structures therefor; Storage structures
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching

Abstract

XML table indexes provide a more efficient mechanism for searching data stored in aggregate form. XML table indexes are a set of tables created to project out in column form commonly sought metadata from stored XML documents. By projecting the data includes into column form, queries on the XML documents can be efficiently processed as they can leverage the enhanced functionality provided by the database tables. The XML table indexes may use aliases, partitioning, constraints and other functions to further improve query flexibility and performance.

Claims

1. A method for indexing a collection of XML documents comprising performing a machine-executed operation involving instructions, wherein the machine-executed operation is at least one of:

A) sending said instructions over transmission media;

B) receiving said instructions over transmission media;

C) storing said instructions onto a machine-readable storage medium; and

D) executing the instructions;

wherein said instructions are instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of;

storing said collection of XML documents in one or more base database structures managed by a database system for storing said collection of XML documents;

based on first data, the database system creating a table, separate from said one or more base database structures, that indexes said collection of XML documents, wherein said table includes a plurality of columns, each column of said plurality of columns corresponding to a different item contained in said collection of XML documents and containing values of said different item; and

wherein said first data indicates, for each column of said plurality of columns, the different item that corresponds to the column.

2. The method of claim 1, further comprising:

receiving a new XML document to store in said collection of XML documents;

extracting a new set of values from the new XML document, wherein each value in said set of new values corresponds to a different item contained in said collection of XML documents; and

populating each column of said plurality of columns from said table with the new set of values extracted from the new XML document.

3. The method of claim 1, wherein the different item includes at least one of nodes, elements, expressions, attributes, and values derived from the expressions in the table.

4. The method of claim 1, wherein the table is created by executing Data Definition Language instructions received from a user.

5. The method of claim 1, wherein the first data includes a first XML document template submitted to the database system.

6. The method of claim 2, wherein the new set of values extracted from the XML document includes XML type data.

7. The method of claim 1, wherein the new set of values extracted from the XML document corresponds to common search elements.

8. The method of claim 1, wherein the table includes one or more references to a set of additional tables, wherein the one or more references to the set of additional tables creates a table chain.

9. The method of claim 1, further comprising:

partitioning said table into one or more partitions.

10. The method of claim 9, wherein the partitioning includes executing the create command with one or more partitioning instructions.

11. The method of claim 9, wherein the partitioning corresponds to the partitioning of the one or more database structures.

12. The method of claim 1, wherein the collection of XML documents is stored in aggregate storage.

13. The method of claim 1, wherein the collection of XML documents is stored object-relationally.

14. The method of claim 2, wherein a column from said plurality of columns maps to two or more items.

15. The method of claim 14, wherein a set of values corresponding to the two or more items are stored in the column from said plurality of columns that maps to two or more items.

16. The method of claim 1, further comprising creating a set of secondary indexes for the table.

17. The method of claim 1, wherein the table includes at least one column of said plurality of columns that stores node hierarchical order information.

18. The method of claim 1, further comprising:

intercepting a user-submitted query on the collection of XML documents; and

rewriting the user-submitted query on the collection of XML documents to access the table.

19. The method of claim 12, further comprising:

intercepting a user-submitted query on the collection of XML documents; and

rewriting the user-submitted query on the collection of XML documents to access the table.

20. The method of claim 19, wherein rewriting the user-submitted query includes mapping the user-submitted query to two or more partitions of the table.

21. The method of claim 18, further comprising:

analyzing the user-submitted query to determine a frequently accessed item from the collection of XML documents; and

automatically adding a new column to the table for the frequently accessed item.

22. A machine-readable storage medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the following steps:

storing said collection of XML documents in one or more base database structures managed by a database system for storing said collection of XML documents;

based on first data, the database system creating a table, separate from said one or more base database structures, that indexes said collection of XML documents, wherein said table includes a plurality of columns, each column of said plurality of columns corresponding to a different item contained in said collection of XML documents and containing values of said different item; and

wherein said first data indicates, for each column of said plurality of columns, the different item that corresponds to the column.

23. The machine-readable storage medium of claim 22, further comprising:

instructions for receiving a new XML document to store in said collection of XML documents;

instructions for extracting a new set of values from the new XML document, wherein each value in said set of new values corresponds to a different item contained in said collection of XML documents; and

instructions for populating each column of said plurality of columns from said tables with the new set of values extracted from the new XML document.

24. The machine-readable storage medium of claim 22, wherein the different item includes at least one of nodes, elements, expressions, attributes, and values derived from the expressions in the table.

25. The machine-readable storage medium of claim 22, wherein the table is created by executing Data Definition Language instructions received from a user.

26. The machine-readable storage medium of claim 22, wherein the first data includes a first XML document template submitted to the database system.

27. The machine-readable storage medium of claim 23, wherein the new set of values extracted from the XML document includes XML type data.

28. The machine-readable storage medium of claim 22, wherein the new set of values extracted from the XML document corresponds to common search elements.

29. The machine-readable storage medium of claim 22, wherein the table includes one or more references to a set of additional tables, wherein the one or more references to the set of additional tables creates a chain.

30. The machine-readable storage medium of claim 22, further comprising:

instructions for partitioning said table into one or more partitions.

31. The machine-readable storage medium of claim 30, wherein the partitioning includes executing the create command with one or more partitioning instructions.

32. The machine-readable storage medium of claim 30, wherein the partitioning corresponds to the partitioning of the one or more database structures.

33. The machine-readable storage medium of claim 22, wherein the collection of XML documents is stored in aggregate storage.

34. The machine-readable storage medium of claim 22, wherein the collection of XML documents is stored object-relationally.

35. The machine-readable storage medium of claim 23, wherein a column from said plurality of columns maps to two or more items.

36. The machine-readable storage medium of claim 35, wherein a set of values corresponding to the two or more items are stored in the column from said plurality of columns that maps to two or more items.

37. The machine-readable storage medium of claim 22, further comprising creating a set of secondary indexes for the table.

38. The machine-readable storage medium of claim 22, wherein the table includes at least one column of said plurality of columns that stores node hierarchical order information.

39. The machine-readable storage medium of claim 22, further comprising:

intercepting a user-submitted query on the collection of XML documents; and

rewriting the user-submitted query on the collection of XML documents to access the table.

40. The machine-readable storage medium of claim 23, further comprising:

instructions for intercepting a user-submitted query on the collection of XML documents; and

instructions for rewriting the user-submitted query on the collection of XML documents to access the table.

41. The machine-readable storage medium of claim 40, wherein rewriting the user-submitted query includes mapping the user-submitted query to two or more partitions of the table.

42. The machine-readable storage medium of claim 39, further comprising:

analyzing the user-submitted query to determine a frequently accessed item from the collection of XML documents; and

automatically adding a new column to the table for the frequently accessed item.