Method and apparatus for elegant mapping between data models

• US 7,756,882 B2
• Filed: 10/01/2004
• Issued: 07/13/2010
• Est. Priority Date: 10/01/2004
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Schach, David N., Aharoni, Avner Y., Meijer, Erik
• Primary Examiner(s): Trujillo; James
• Assistant Examiner(s): CONYERS, DAWAUNE A
• Application Number:
  US10/957,516
• Publication Number:
  US 20060101423A1
• Time in Patent Office: 2,111 Days
• Field of Search: 709/246, 707/1, 707/101
• US Class Current: 707/756
• CPC Class Codes: G06F 16/8358 Query translation
• CPC Class Codes: G06F 16/86 Mapping to a database

Abstract

Data is requested by an XML application conforming to the XML data model. The data is stored in an SQL database conforming to the relational data model. A mapping component transforms the XML query into an SQL query using a mapping component comprising instructions obtained from an instruction set defined by a mapping algebra. The transformed operation is used to retrieve the data. Once retrieved, the algebraically defined mapping component transforms the SQL data from data conforming to the relational data model to data conforming to the XML data for use in the XML application.

Claims

1. A computing device including a processing unit, the computing device also including:

a software transformation element comprising instructions executed by the processing unit, the software transformation element causing transformation of data conforming to a first data model into data conforming to a second data model,

wherein the instructions in said software transformation element are obtained from a set of programming language instructions that are semantically defined by mapping algebra for executing a bi-directional and compositional mapping between the first and the second data models, wherein the bi-directional mapping comprises;

a read operation that transforms a value of a source type to a value of a mapped target type, in accordance with a floor function of an algebraic expression; and

an update operation that takes the value of the source type and the value of the mapped target type and reconstructs therefrom, a modified value of the source type, in accordance with a ceiling function of the algebraic expression; and

the compositional mapping comprises at least one of an associative read operation using a pair of algebraic expressions, or an associative write operation using the pair of algebraic expressions.

2. The computing device of claim 1 wherein the instructions in said software transformation element also comprise instructions mapping particular metadata characteristics of the data conforming to the first data model to metadata characteristics of the other data conforming to the second data model.

3. The computing device of claim 2 where the metadata characteristics of the data conforming to the first data model comprise first structural characteristics of the first data model, the metadata characteristics of the other data conforming to the second data model comprise second structural characteristics of the second data model, and the instructions in said software transformation element comprise instructions mapping the first structural characteristics of the data conforming to the first data model to the second structural characteristics of the other data conforming to the second data model.

4. The computing device of claim 2 where the metadata characteristics of the data conforming to the first data model comprise first field characteristics of the first data model, the metadata characteristics of the other data conforming to the second data model comprise second field characteristics of the second data model, and the instructions in said software transformation element comprise instructions mapping the first field characteristics of the data conforming to the first data model to the second field characteristics of the other data conforming to the second data model.

5. The computing device of claim 2 where the metadata characteristics of the data conforming to the first data model comprise first relationship characteristics of the first data model, the metadata characteristics of the other data conforming to the second data model comprise second relationship characteristics of the second data model, and the instructions in said software transformation element comprise instructions mapping the first relationship characteristics of the data conforming to the first data model to the second relationship characteristics of the other data conforming to the second data model.

6. The computing device of claim 1 where the first data model is a relational database data model.

7. The computing device of claim 6 where the second data model is an xml data model.

8. The computing device of claim 6 where the second data model is an object data model.

9. The computing device of claim 1 where the first data model is an xml data model.

10. The computing device of claim 9 where the second data model is a relational database data model.

11. The computing de\ice of claim 1 where the first data model is an object data model.

12. The computing device of claim 11 where the second data model is a relational database data model.

13. The computing device of claim 1 wherein the bi-directional read function incorporates a first expression M in a first identity transformation ┌

M┐

(└

M┘

(t),t)=t whereby a value of a source type T is transformed to a value of a mapped target type T.M.

14. The computing device of claim 13 wherein the bi-directional update function incorporates the first expression M in a second identity transformation └

M┘

(└

M┘

(t),t)=t whereby the value of the source type T and the value of the mapped target type T.M are used to reconstruct a modified value of the source type T.

15. The computing device of claim 14 wherein the compositional read function incorporates the first expression M wad the second expression N for satisfying a third identity transformation └

M┘

(└

N┘

t)=└

M.N┘

(t).

16. The computing device of claim 15 wherein the compositional read function incorporates the first expression M and the second expression N for satisfying a fourth identity transformation ┌

M┐

(┌

M┐

t,r)=┌

M.N┐

(t,r).

17. A method for transforming data in a computer, the method comprising the steps of:

generating a first request in a software application of the computer; and

transforming the first request conforming to structure, field and relationship data within a first data model into a second request conforming to structure, field and relationship data within a second data model using a set of programming language instructions that are semantically defined by mapping algebra operators;

said mapping algebra operators are selected for executing a bidirectional and compositional mapping between a target and a source, wherein;

said bidirectional and compositional mapping is materialized using a type-based query language of the second data model and translated thereon into a type-based query language of the first data model for carrying out at least one of a) reading a data value from the source to the target, transforming the read data value using said mapping algebra operators, and then writing the transformed result back to the source, or b) writing a data value from the target to the source, transforming the written data value using said mapping algebra operators, and then reading the transformed value back to the target;

the bi-directional mapping comprises;

a read operation that transforms a value of a source type to a value of a mapped target type, in accordance with a floor function of an algebraic expression; and

an update operation that takes the value of the source type and the value of the mapped target type and reconstructs therefore, a modified value of the source type, in accordance with a ceiling function of the algebraic expression; and

the compositional mapping comprises at least one of an associative read operation using a pair of algebraic expressions, or an associative write operation using the pair of algebraic expressions.

18. The method of claim 17 wherein the step of transforming the first request conforming to the first data model comprises mapping particular metadata characteristics of data conforming to the first data model to metadata characteristics of data conforming to the second data model.

19. The method of claim 18 where the metadata characteristics of the data conforming to the first data model comprise first structural characteristics of the first data model, the metadata characteristics of the data conforming to the second model comprise second structural characteristics of the second data model, and the mapping step further comprises mapping the first structural characteristics of the data conforming to the first data model to the second structural characteristics of the data conforming to the second data model.

20. The method of claim 18 where the metadata characteristics of the data conforming to the first data model comprise first field characteristics of the first data model, the metadata characteristics of the data conforming to the second model comprise second field characteristics of the second data model, and the mapping step further comprises mapping the first held characteristics of the data conforming to the first data model to file second field characteristics of the data conforming to the second data model.

21. The method of claim 18 where the metadata characteristics of the data conforming to the first data model comprise first relationship characteristics of the first data model, the metadata characteristics of the data conforming to the second model comprise second relationship characteristics of the second data model, and the mapping step further comprises mapping the first relationship characteristics of the data conforming to the first data model to the second relationship characteristics of the data conforming to the second data model.

22. The method of claim 17 where the first data model is a relational database data model.

23. The method of claim 22 where the second data model is an xml data model.

24. The method of claim 22 where the second data model is an object data model.

25. The method of claim 17 where the first data model is an xml data model.

26. The method of claim 25 where the second data model is a relational database data model.

27. The method of claim 17 where the first data model is an object data model.

28. The method of claim 27 where the second data model is a relational database data model.

29. The method of claim 17 wherein said mapping algebra comprises a set of mapping expressions that define mapping operations performed on data types.

30. A computer-readable medium having computer-executable instructions for performing steps comprising:

transforming structure, field and relationship data conforming to a first data model into structure, field and relationship data conforming to a second data model, by using a set of programming language instructions that are semantically defined by mapping algebra operators, wherein the mapping algebra operators are executed for providing a bi-directional and compositional mapping between the first and the second data models, the mapping materialized using a type-based query language of the second data model and translated thereon into a type-based query language of the first data model for carrying out at least one of a) reading a data value from a source to a target, transforming the read data value using said mapping algebra operators, and then writing the transformed result back to the source, or b) writing a data value from the target to the source, transforming the written data value using said mapping algebra operators, and then reading the transformed value back to the target, wherein;

the bi-directional mapping comprises;

a reading operation that transforms a value of a source type to a value of a mapped target type, in accordance with a floor function of an algebraic expression; and

an update operation that takes the value of the source type and the value of the mapped target type and reconstructs therefrom, a modified value of the source type, in accordance with a ceiling function of the algebraic expression; and

the compositional mapping comprises at least one of an associative read operation using a pair of algebraic expressions, or an associative write operation using the pair of algebraic expressions.

31. The computer-readable medium of claim 30 where the step of bidirectional and compositional mapping comprises mapping particular metadata characteristics of data conforming to the first data model to metadata characteristics of the other data conforming to the second data model.

32. The computer-readable medium of claim 31 where the metadata characteristics of the data conforming to the first data model comprise first structural characteristics of the first data model, the metadata characteristics of the other data conforming to the second model comprise second structural characteristics of the second data model, and the mapping step further comprises mapping the first structural characteristics of the data conforming to the first data model to the second structural characteristics of the other data conforming to the second data model.

33. The computer-readable medium of claim 31 where the metadata characteristics of the data conforming to the first data model comprise first field characteristics of file first data model, the metadata characteristics o % the other data conforming to the second model comprise second field characteristics of the second data model, and the mapping step further comprises mapping the first field characteristics of the data conforming to the first data model to the second field characteristics of the other data conforming to the second data model.

34. The computer-readable medium of claim 31 where the metadata characteristics of the data conforming to the first data model comprise first relationship characteristics of the first data model, the metadata characteristics of the other data conforming to the second model comprise second relationship characteristics of the second data model, and the mapping step further comprises mapping the first relationship characteristics of the data conforming to the first data model to the second relationship characteristics of the other data conforming to the second data model.

35. The computer-readable medium of claim 30 where the first data model is a relational database data model.

36. The computer-readable medium of claim 35 where the second data model is an xml data model.

37. The computer-readable medium of claim 35 where the second data model is an object data model.

38. The computer-readable medium of claim 35 where the first data model is an xml data model.

39. The computer-readable medium of claim 38 where the second data model is a relational database data model.

40. The computer-readable medium of claim 30 where the first data model is an object data model.

41. The computer-readable medium of claim 40 where the second data model is a relational database data model.

42. The computer-readable medium of claim 30 wherein said mapping algebra comprises a set of mapping expressions that define mapping operations performed on data types.