Universal output constructor for XML queries universal output constructor for XML queries

• US 6,766,330 B1
• Filed: 10/12/2000
• Issued: 07/20/2004
• Est. Priority Date: 10/19/1999
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chen, Shyh-Kwei, Lo, Ming-Ling
• Primary Examiner(s): Robinson, Greta
• Assistant Examiner(s): PANNALA, SATHYANARAYA R
• Application Number:
  US09/689,377
• Time in Patent Office: 1,377 Days
• Field of Search: 707/1-10, 707/102, 707/203
• US Class Current: 1/1
• CPC Class Codes: G06F 16/84 Mapping; Conversion
• CPC Class Codes: Y10S 707/99935 Query augmenting and refining, e.g. inexact access
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

Methods and apparatus are provided according to the present invention which guarantee that an Extensible Markup Language (XML) query output conforms to a Document Type Definition (DTD) of the user'"'"'s choice. The present invention allows for: (i) selection of a DTD; (2) integration of one or more XML queries with the DTD; and (iii) in accordance with the provided algorithm, automatic generation of a valid output XML document conforming to the DTD, using the data selected by the XML queries as content of the XML document.

Claims

1. A method of processing one or more extensible Markup Language (XML) queries, the method comprising the steps of:

generating a mapping construct which maps a predetermined document type definition (DTD) to one or more data sources to be accessed in response to the one or more XML queries, the mapping construct including a binding specification wherein the one or more XML queries are bound to one or more binding variables;

evaluating the one or more XML queries in accordance with the binding specification of the mapping construct and assigning the evaluation result to the one or more binding variables; and

generating an XML document resulting from the query evaluation, wherein the resulting XML document conforms to the predetermined DTD.

2. The method of claim 1, wherein the one or more XML queries are written in one or more XML query languages.

3. The method of claim 1, wherein the resulting XML document is a combination of more than one XML query associated with one or more query languages.

4. The method of claim 1, wherein the resulting XML document is a combination of one or more XML queries and one or more non-XML queries.

5. The method of claim 1, wherein the DTD is specified by a user.

6. The method of claim 1, wherein the mapping construct generation step comprises the steps of:

determining suitable DTD constructs;

binding the constructs to variables;

associating the variables with a partial XML result obtained from scoping and filtering stages of the XML query; and

distributing the variables to suitable DTD constructs with value functions.

7. The method of claim 6, further comprising the step of accepting scalar-based results from the scoping and filtering stages.

8. The method of claim 6, further comprising the step of accepting subtree-based results from the scoping and filtering stages.

9. The method of claim 6, further comprising the step of allowing the bindings to be used as parameters in at least one of value generation functions and other binding functions.

10. The method of claim 6, further comprising the step of resolving a nested or recursive filtering query construct with sequential cascade binding constructs.

11. The method of claim 1, wherein the query evaluation step comprises the step of combining different parsing and evaluating mechanisms for evaluating XML queries from different XML query languages.

12. The method of claim 11, further comprising the step of allowing binding variables to be used in one or more XML queries of different query languages.

13. The method in claim 11, further comprising the step of evaluating one or more XML queries of different query languages with binding variables as parameters.

14. The method of claim 1, wherein the resulting XML document generation step comprises the steps of:

recursively traversing DTD constructs from a root element; and

associating with binding variables after one of resolving binding functions and evaluating XML queries, until reaching a leaf construct, where a partial XML result is obtained by evaluating associated value functions.

15. The method of claim 14, wherein the resulting XML document is composed during a traversal returning stage by adding XML tags enclosing the partial XML result.

16. Apparatus for processing one or more extensible Markup Language (XML) queries, the apparatus comprising the steps of:

at least one processor operative to;

(i) generate a mapping construct which maps a predetermined document type definition (DTD) to one or more data sources to be accessed in response to the one or more XML queries, the mapping construct including a binding specification wherein the one or more XML queries are bound to one or more binding variables;

(ii) evaluate the one or more XML queries in accordance with the binding specification of the mapping construct and assigning the evaluation result to the one or more binding variables; and

(iii) generate an XML document resulting from the query evaluation, wherein the resulting XML document conforms to the predetermined DTD.

17. The apparatus of claim 16, wherein the one or more XML queries are written in one or more XML query languages.

18. The apparatus of claim 16, wherein the resulting XML document is a combination of more than one XML query associated with one or more query languages.

19. The apparatus of claim 16, wherein the resulting XML document is a combination of one or more XML queries and one or more non-XML queries.

20. The apparatus of claim 16, wherein the DTD is specified by a user.

21. The apparatus of claim 16, wherein the mapping construct generation operation comprises:

(i) determining suitable DTD constructs;

(ii) binding the constructs to variables;

(iii) associating the variables with a partial XML result obtained from scoping and filtering stages of the XML query; and

(iv) distributing the variables to suitable DTD constructs with value functions.

22. The apparatus of claim 21, wherein the at least one processor is further operative to accept scalar-based results from the scoping and filtering stages.

23. The apparatus of claim 21, wherein the at least one processor is further operative to accept subtree-based results from the scoping and filtering stages.

24. The apparatus of claim 21, wherein the at least one processor is further operative to allow the bindings to be used as parameters in at least one of value generation functions and other binding functions.

25. The apparatus of claim 21, wherein the at least one processor is further operative to resolve a nested or recursive filtering query construct with sequential cascade binding constructs.

26. The apparatus of claim 16, wherein the query evaluation operation comprises combining different parsing and evaluating mechanisms for evaluating XML queries from different XML query languages.

27. The apparatus of claim 26, wherein the at least one processor is further operative to allow binding variables to be used in one or more XML queries of different query languages.

28. The apparatus in claim 26, wherein the at least one processor is further operative to evaluate one or more XML queries of different query languages with binding variables as parameters.

29. The apparatus of claim 16, wherein the resulting XML document generation operation comprises:

(i) recursively traversing DTD constructs from a root element; and

(ii) associating with binding variables after one of resolving binding functions and evaluating XML queries, until reaching a leaf construct, where a partial XML result is obtained by evaluating associated value functions.

30. The apparatus of claim 29, wherein the resulting XML document is composed during a traversal returning stage by adding XML tags enclosing the partial XML result.

31. An article of manufacture for processing one or more eXtensible Markup Language (XML) queries, comprising a machine readable medium containing one or more programs which when executed implement the steps of:

generating a mapping construct which maps a predetermined document type definition (DTD) to one or more data sources to be accessed in response to the one or more XML queries, the mapping construct including a binding specification wherein the one or more XML queries are bound to one or more binding variables;

evaluating the one or more XML queries in accordance with the binding specification of the mapping construct and assigning the evaluation result to the one or more binding variables; and

generating an XML document resulting from the query evaluation, wherein the resulting XML document conforms to the predetermined DTD.

32. Computer-based apparatus for processing one or more eXtensible Markup Language (XML) queries, the apparatus comprising:

a document retrieval engine responsive to the one or more XML queries and to a predetermined mapping construct which maps a predetermined document type definition (DTD) to one or more data sources to be accessed in response to the one or more XML queries, wherein the document retrieval engine is operative to (i) evaluate the one or more XML queries in accordance with the mapping construct; and

(ii) generate an XML document resulting from the query evaluation, wherein the resulting XML document conforms to the predetermined DTD.

33. A method of processing one or more extensible Markup Language (XML) queries, the method comprising the steps of:

generating a mapping construct which maps a predetermined document type definition (DTD) to one or more data sources to be accessed in response to the one or more XML queries;

evaluating the one or more XML queries in accordance with the mapping construct; and

generating an XML document resulting from the query evaluation.