FAST EXTRACTION OF SCALAR VALUES FROM BINARY ENCODED XML

• US 20090307239A1
• Filed: 06/06/2008
• Published: 12/10/2009
• Est. Priority Date: 06/06/2008
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Zhang, Ning, Idicula, Sam, Chandrasekar, Sivasankaran, Agarwal, Nipun
• Granted Patent: US 8,429,196 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/83 Querying

Abstract

Techniques are provided for efficiently extracting scalar values from binary-encoded XML data. Node information is stored in association with binary-encoded XML data to indicate whether one or more nodes of an XML document are simple or complex. A node is simple if the node has no child elements and no attributes. The node information of a particular node is used to determine whether a particular node, identified in a query, is simple or complex. If the particular node is simple, then the scalar value of the particular node is identified without performing any operations other than possibly converting the scalar value to a non-binary-encoded format or converting the scalar value to a value of a different data type.

Claims

1. A method comprising:

receiving a query that specifies one or more XML nodes that are binary-encoded;

in response to receiving the query, requesting binary-encoded XML data from one or more data sources;

receiving at least a subset of the binary-encoded XML data;

determining, from node information associated with the subset of the binary-encoded XML data, that a particular node, of the one or more XML nodes, is simple, wherein a node is simple if the node has no child elements and no associated attributes; and

in response to determining that the particular node is simple, identifying the scalar value of the particular node in the subset of the binary-encoded XML data.

2. The method of claim 1, further comprising converting the scalar value of the particular node into a non-binary-encoded format.

3. The method of claim 2, wherein converting the scalar value of the particular node into a non-binary-encoded format is performed after the scalar value is identified.

4. The method of claim 1, further comprising:

in response to determining that the particular node is not simple, using an XPath evaluation engine to evaluate any text descendants of the particular node.

5. The method of claim 1, further comprising converting the scalar value into a particular data type that is specified in the query or that is specified in an XML schema associated with the binary-encoded XML data.

6. The method of claim 5, wherein:

before converting, the data type of the scalar value is a string; and

the particular data type is one of a number data type, a date data type, a float data type, or a Boolean data type.

7. The method of claim 1, further comprising:

before receiving the query, storing XML data according to data types specified in an XML schema to which the XML data conforms,

wherein converting the scalar value to a different data type is unnecessary.

8. The method of claim 1, wherein the node information is stored within the subset of the binary-encoded XML data or is stored within an XML schema to which the binary-encoded XML data conforms.

11. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 1.

12. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 2.

13. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 3.

14. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 4.

15. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 5.

16. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 6.

17. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 7.

18. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 8.

9. A computer-implemented method comprising:

determining that a node in an XML representation contains an XML value to extract;

before extracting the XML value, determining whether the node is simple or complex, wherein a node is simple if the node has no child elements and no associated attributes, wherein a node is complex if the node has at least one child element or at least one attribute; and

in response to determining that the node is simple, extracting the XML value from the XML representation.

10. The method of claim 9, wherein the XML representation is a binary-encoding of one or more nodes of an XML document.

19. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 9.

20. A machine-readable storage medium carrying instructions which, when executed by one or more processors, cause the one or more processors to perform the method recited in claim 10.