Remote data access and integration of distributed data sources through data schema and query abstraction

• US 20030208458A1
• Filed: 04/25/2002
• Published: 11/06/2003
• Est. Priority Date: 04/25/2002
• Status: Active Grant

• Current Assignee: Workday Incorporated
• Original Assignee: International Business Machines Corporation
• Inventors: Stevens, Richard Joseph, Dettinger, Richard Dean
• Granted Patent: US 6,954,748 B2
• Time in Patent Office: Days
• US Class Current: 707/1
• CPC Class Codes: G06F 16/2452 Query translation
• CPC Class Codes: G06F 16/2471 Distributed queries
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99934 Query formulation, input preparation, or translation

Abstract

The present invention generally is directed to a system, method and article of manufacture for accessing data independent of the particular manner in which the data is physically represented. In one embodiment, a data repository abstraction layer provides a logical view of the underlying data repository that is independent of the particular manner of data representation. In one embodiment, the data repository abstraction layer specifies a location of data in a repository and a method for accessing the data. A query abstraction layer is also provided and is based on the data repository abstraction layer. A runtime component performs translation of an abstract query into a form that can be used against a particular physical data representation.

Claims

1. A method of providing access to data in an environment of multiple data repositories, comprising:

providing, for a requesting entity, a query specification comprising a plurality of logical fields for defining an abstract query; and

for each of the plurality of logical fields, providing an access method which specifies at least a method for accessing the data and a location of the data.

2. The method of claim 1, further comprising:

issuing the abstract query by the requesting entity according to the query specification;

transforming the abstract query into a query consistent with a particular physical data representation of the data; and

accessing a data repository specified by the location in the access method for the physical entity of the data for a particular logical field of the plurality of logical fields.

3. The method of claim 2, where the query consistent with the particular physical data representation is one of a SQL query, an XML query and a procedural request.

4. The method of claim 2, wherein transforming the abstract query into the query consistent with the particular physical data representation comprises partitioning the abstract query into sub-queries grouped according to access method types.

5. The method of claim 4, wherein the access method types are selected from a group comprising an SQL query type, an XML query type and a procedural request type.

6. A method of accessing data in an environment of multiple data repositories, comprising:

issuing, by a requesting entity, an abstract query according to a query specification of the requesting entity;

wherein the query specification provides a definition for a plurality of logical fields of the abstract query; and

transforming the abstract query into a query consistent with a particular physical data representation of the data according to access methods which map the logical fields to physical entities of the data by defining a method for accessing each of the physical entities and a location for each of the physical entities.

7. The method of claim 6, further comprising accessing a data repository specified by the location for a physical entity of the data for a particular logical field of the plurality of logical fields.

8. The method of claim 6, wherein the abstract query comprises at least one selection criterion and a result specification.

9. The method of claim 6, further comprising:

for a physical entity of the data for a particular logical field of the plurality of logical fields, determining whether the physical entity of the data is located in a local cache; and

if not, accessing a data repository specified by the location in the access method for the physical entity of the data.

10. The method of claim 6, wherein transforming the abstract query into the query consistent with the particular physical data representation comprises partitioning the abstract query into sub-queries grouped according to access method types.

11. The method of claim 10, wherein the access method types are selected from a group comprising an SQL query type, an XML query type and a procedural request type.

12. A computer-readable medium containing a program which, when executed by a processor, performs an operation of providing access to data in an environment of multiple data repositories, the program comprising:

a query specification for a requesting entity, the query specification comprising a plurality of logical fields for defining an abstract query; and

an access method for each logical field each of which defines a method for accessing a physical entity of the data and a plurality of parameters to be passed to the method for accessing the physical entity, wherein at least one parameter is a location parameter specifying a location of a data source containing the physical entity.

13. The computer-readable medium of claim 12, where the query consistent with the particular physical data representation is one of a SQL query, XML query and a procedural request.

14. The computer-readable medium of claim 12, wherein the requesting entity is an application.

15. The computer-readable medium of claim 12, wherein the operation further comprises:

for the physical entity of the data for a particular logical field of the plurality of logical fields, determining whether the physical entity of the data is located in a local cache; and

if not, accessing a data repository specified by the location in the access method for the physical entity of the data.

16. The computer-readable medium of claim 12, wherein each of the plurality of access methods define a particular physical representation and a location of the respective physical entity of the data.

17. The computer-readable medium of claim 12, wherein the operation comprises:

issuing the abstract query by the requesting entity according to the query specification;

transforming the abstract query into a query consistent with the particular physical data representation; and

accessing a data repository specified by the location for the physical entity of the data for a particular logical field of the plurality of logical fields.

18. The computer-readable medium of claim 17, wherein transforming the abstract query into the query consistent with the particular physical data representation comprises partitioning the abstract query into sub-queries grouped according to access method types.

19. The computer-readable medium of claim 18, wherein the access method types are selected from a group comprising an SQL query type, an XML query type and a procedural request type.

20. A computer-readable medium containing a program which, when executed by a processor, performs an operation of accessing data having a particular physical data representation, the operation comprising:

issuing, by a requesting entity, an abstract query according to a query specification of the requesting entity;

wherein the query specification provides a definition for logical fields of the abstract query; and

transforming the abstract query into a query consistent with a particular physical data representation of the data according to access methods which map the logical fields to physical entities of the data by defining, for each of the physical entities, at least a method for accessing the physical entity and a location of the physical entity.

21. The computer-readable medium of claim 20, wherein the operation further comprises accessing a data repository specified by the location for the physical entity of the data for a particular logical field of the plurality of logical fields.

22. The computer-readable medium of claim 20, wherein the abstract query comprises at least one selection criterion and a result specification.

23. The computer-readable medium of claim 20, wherein the operation further comprises:

for the physical entity of the data for a particular logical field of the plurality of logical fields, determining whether the physical entity of the data is located in a local cache; and

if not, accessing a data repository specified by the location in the access method for the physical entity of the data.

24. The computer-readable medium of claim 20, wherein transforming the abstract query into the query consistent with the particular physical data representation comprises partitioning the abstract query into sub-queries grouped according to access method types.

25. The computer-readable medium of claim 24, wherein the access method types are selected from a group comprising an SQL query type, an XML query type and a procedural request type.

26. A computer, comprising:

a memory containing at least (i) a requesting entity comprising a query specification providing a definition for an abstract query comprising a plurality of logical fields, (ii) a data repository abstraction component comprising mapping rules which map the logical fields to physical entities of data, wherein the mapping rules comprise location specifications for each of at least a portion of the logical fields of the abstract query, and wherein each of the location specifications specify a location of a data source containing a physical entity to be accessed; and

(iii) a runtime component for transforming the abstract query into a query consistent with the physical entities of data according to the mapping rules; and

a processor adapted to execute contents of the memory.

27. The computer of claim 26, wherein a first portion of the data sources specified by the respective location specification are local and a second portion are remote.

28. The computer of claim 26, wherein transforming the abstract query into the query consistent with the particular physical data representation comprises partitioning the abstract query into sub-queries grouped according to access method types.

29. The computer of claim 28, wherein the access method types are selected from a group comprising an SQL query type, an XML query type and a procedural request type.