Document fidelity with binary XML storage

• US 8,090,731 B2
• Filed: 07/28/2008
• Issued: 01/03/2012
• Est. Priority Date: 10/29/2007
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Sthanikam, Balasubramanyam, Chandrasekar, Sivasankaran, Agarwal, Nipun, Idicula, Sam, Medi, Vijay
• Primary Examiner(s): Lewis, Cheryl
• Assistant Examiner(s): Waldron, Scott A
• Application Number:
  US12/180,760
• Publication Number:
  US 20090112902A1
• Time in Patent Office: 1,254 Days
• Field of Search: None
• US Class Current: 707/756
• CPC Class Codes: G06F 16/258 Data format conversion from or to a database
• CPC Class Codes: G06F 16/80 of semi-structured data, e.g. markup language structured data such as SGML, XML or HTML content-based retrieval of web data G06F16/95

Abstract

Techniques are provided for ensuring lexical fidelity when an XML document is stored in a binary format. Operations, on the XML data, that would cause the loss of lexical fidelity between the original XML document and the binary-encoded version of the XML document are not performed. Such operations include the removal of unnecessary whitespace characters, certain data type conversions, CRLF normalization, the “collapsing” of two-tag empty elements into a single tag empty element, and the replacing of entity references or numeric character references with another value. An XML schema, to which the XML document conforms, may indicate that the XML document is to be stored in a lexical fidelity mode. Additionally, or alternatively, the database statement that (when executed) causes the XML document to be stored in a binary format may so indicate.

Claims

1. A method comprising:

receiving Extensible Markup Language (XML) data that is not encoded in a binary format;

in response to receiving the XML data, using a binary encoding technique to encode the XML data in a binary format to create a binary version of the XML data that is lexically equivalent to the XML data, wherein each character in the XML data is represented in the binary version;

wherein using a binary encoding technique comprises performing at least one of;

encoding one or more unnecessary whitespace characters that are in a particular element tag in the XML data,

encoding a carriage return character and a line feed character that appear consecutively in the XML data, or

encoding an empty XML element that comprises an opening tag and a closing tag by encoding the opening tag and the closing tag in the binary format;

storing the binary version of the XML data in persistent storage;

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

2. The method of claim 1, further comprising:

receiving a request that requires at least a portion of the binary version of the XML data; and

in response to the request, retrieving the portion from the persistent storage, wherein the portion is lexically equivalent to the corresponding portion of the XML data.

3. The method of claim 1, further comprising, before the XML data is encoded in the binary format, receiving a lexical indication that indicates that the binary version of the XML data must be lexically equivalent to the XML data.

4. The method of claim 3, wherein the lexical indication is included in one or more of (1) a data definition language (DDL) statement that, when executed, causes the XML data to be encoded in the binary format or (2) an XML schema to which the XML data conforms.

5. The method of claim 1, wherein:

the XML data includes one or more unnecessary whitespace characters; and

the binary-version of the XML data includes the one or more unnecessary whitespace characters.

6. The method of claim 1, wherein using the binary encoding technique comprises:

encoding a carriage return character and a line feed character that appear consecutively in the XML data.

7. The method of claim 1, wherein using the binary encoding technique comprises:

encoding the content of an element that is included in the XML data and that includes a number data type in the binary format as a string data type.

8. The method of claim 1, wherein using the binary encoding technique comprises:

encoding an empty XML element that is included in the XML data and that comprises an opening tag and a closing tag by opening tag and the closing tag in the binary format.

9. The method of claim 1, wherein using the binary encoding technique comprises:

encoding a reference that is included in the XML data and that is one of an entity reference or a numeric character reference in the binary format without replacing the reference with another value.

10. The method of claim 9, wherein:

the reference is a user-defined entity reference that corresponds to an entity value, and

using the binary encoding technique comprises encoding the user-defined entity in the binary format without replacing the user-defined entity reference with the entity value.

11. The method of claim 1, wherein using the binary encoding technique comprises:

encoding one or more unnecessary whitespace characters that are in a particular element tag in the XML data.

12. The method of claim 1, further comprising:

retrieving the binary version of the XML data from persistent storage; and

decoding the binary version of the XML data to create a non-binary version of the XML data, wherein the non-binary version of the XML data is the same as the XML data that was received.

13. A method comprising:

determining whether a lexical fidelity mode for binary storage has been selected for an XML document that is to be stored in a binary format, wherein if the lexical fidelity mode has been selected for a particular XML document, then each character in the particular XML document must be represented in a binary-encoded representation of the particular XML document;

if the lexical fidelity mode has been selected for the XML document, then using a first binary encoding technique to generate an encoded representation of the XML document, that represents all characters in the XML document; and

if the lexical fidelity mode has not been selected for the XML document, then using a second binary encoding technique to generate an encoded representation of the XML document, that does not represent all characters in the XML document, wherein the second binary encoding technique is different than the first binary encoding technique;

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

14. One or more storage media storing instructions which, when executed by one or more processors, causes:

receiving Extensible Markup Language (XML) data that is not encoded in a binary format;

in response to receiving the XML data, using a binary encoding technique to encode the XML data in a binary format to create a binary version of the XML data that is lexically equivalent to the XML data, wherein each character in the XML data is represented in the binary version;

wherein using a binary encoding technique comprises performing at least one of;

encoding one or more unnecessary whitespace characters that are in a particular element tag in the XML data,

encoding a carriage return character and a line feed character that appear consecutively in the XML data, or

encoding an empty XML element that comprises an opening tag and a closing tag by encoding the opening tag and the closing tag in the binary format;

storing the binary version of the XML data in persistent storage.

15. The one or more storage media of claim 14, wherein the instructions, when executed by the one or more processors, further cause:

receiving a request that requires at least a portion of the binary version of the XML data; and

in response to the request, retrieving the portion from the persistent storage, wherein the portion is lexically equivalent to the corresponding portion of the XML data.

16. The one or more storage media of claim 14, further comprising, before the XML data is encoded in the binary format, receiving a lexical indication that indicates that the binary version of the XML data must be lexically equivalent to the XML data.

17. The one or more storage media of claim 16, wherein the lexical indication is included in one or more of (1) a data definition language (DDL) statement that, when executed, causes the XML data to be encoded in the binary format or (2) an XML schema to which the XML data conforms.

18. The one or more storage media of claim 14, wherein:

the XML data includes one or more unnecessary whitespace characters; and

the binary-version of the XML data includes the one or more unnecessary whitespace characters.

19. The one or more storage media of claim 14, wherein using the binary encoding technique comprises:

encoding a carriage return character and a line feed character that appear consecutively in the XML data.

20. The one or more storage media of claim 14, wherein using the binary encoding technique comprises:

encoding the content of an element that is included in the XML data and that includes a number data type in the binary format as a string data type.

21. The one or more storage media of claim 14, wherein using the binary encoding technique comprises:

encoding an empty XML element that is included in the XML data and that comprises an opening tag and a closing tag by encoding the opening tag and the closing tag in the binary format.

22. The one or more storage media of claim 14, wherein using the binary encoding technique comprises:

encoding a reference that is included in the XML data and that is one of an entity reference or a numeric character reference in the binary format without replacing the reference with another value.

23. The one or more storage media of claim 22, wherein:

the reference is a user-defined entity reference that corresponds to an entity value, and

encoding the reference in the binary format comprises encoding the user-defined entity in the binary format without replacing the user-defined entity reference with the entity value.

24. The one or more storage media of claim 14, wherein using the binary encoding technique comprises:

encoding one or more unnecessary whitespace characters that are in a particular element tag in the XML data.

25. The one or more storage media of claim 14, wherein the instructions, when executed by one or more processors, further cause:

retrieving the binary version of the XML data from persistent storage; and

decoding the binary version of the XML data to create a non-binary version of the XML data, wherein the non-binary version of the XML data is the same as the XML data that was received.

26. One or more storage media storing instructions which, when executed by one or more processors, cause:

determining whether a lexical fidelity mode for binary storage has been selected for an XML document that is to be stored in a binary format, wherein if the lexical fidelity mode has been selected for a particular XML document, then each character in the particular XML document must be represented in a binary-encoded representation of the particular XML document;

if the lexical fidelity mode has been selected for the XML document, then using a first binary encoding technique to generate an encoded representation of the XML document, that represents all characters in the XML document; and

if the lexical fidelity mode has not been selected for the XML document, then using a second binary encoding technique to generate an encoded representation of the XML document, that does not represent all characters in the XML document, wherein the second binary encoding technique is different than the first binary encoding technique;

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