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

• US 6,954,748 B2
• Filed: 04/25/2002
• Issued: 10/11/2005
• Est. Priority Date: 04/25/2002
• Status: Expired due to Fees

• Current Assignee: Workday Incorporated
• Original Assignee: International Business Machines Corporation
• Inventors: Stevens, Richard Joseph, Dettinger, Richard Dean
• Primary Examiner(s): LE, UYEN T
• Application Number:
  US10/131,984
• Publication Number:
  US 20030208458A1
• Time in Patent Office: 1,265 Days
• Field of Search: 707 1- 4, 707/103.R, 707/103.Y
• US Class Current: 707/774
• 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 computer-implemented method of providing access to data in an environment of multiple data repositories, comprising:

performing an operation by a computer, the operation comprising;

providing a data abstraction model 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, wherein each access method is of a given type according to the particular physical data representation of the data to be accessed;

receiving the abstract query from a requesting entity, the abstract query having been composed according to a query specification that provides an interface to the data abstraction model;

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

2. The computer-implemented method of claim 1, where the query consistent with the particular physical data representation is one of a SQL query, an XML query and a procedural request.

3. The computer-implemented method of claim 1, wherein the access method types are selected from a group comprising an SQL query, an XML query and a procedural request.

4. A computer-implemented method of accessing data in an environment of multiple data repositories, comprising:

performing en operation by a computer, the operation comprising;

receiving, from a requesting entity, an abstract query according to a query specification of the requesting entity;

wherein the query specification provides an interface to a data abstraction model comprising a definition for each of a plurality of logical fields of the abstract query, each definition of each logical field defining an access method which maps the logical field to a respective physical entity of the data by defining (i) a method for accessing the respective physical entity and (ii) a location for the respective physical entity;

wherein each access method is of a given type according to the particular physical data representation of the data to be accessed; and

transforming the abstract query into a query consistent with a particular physical data representation of the data according to the access methods;

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 the access method types.

5. The method of claim 4, 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.

6. The method of claim 4, wherein the abstract query comprises at least one selection criterion and a result specification.

7. The method of claim 4 wherein transforming comprises:

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, creating query language of the query configured to access a data repository specified by the location in the access method for the physical entity of the data.

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

9. 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:

receiving, from a requesting entity, an abstract query according to a query specification of the requesting entity;

wherein the query specification provides an interface to a data abstraction model comprising a definition for each of a plurality of logical fields of the abstract query, each definition of each logical field defining an access method which maps the logical field to a respective physical entity of the data by defining (i) a method for accessing the respective physical entity and (ii) a location for the respective physical entity;

wherein each access method is of a given type according to the particular physical data representation of the data to be accessed; and

transforming the abstract query into a query consistent with a particular physical data representation of the data according to the access methods;

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 the access method types.

10. The computer-readable medium of claim 9, 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.

11. The computer-readable medium of claim 9, wherein the abstract query comprises at least one selection criterion and a result specification.

12. The computer-readable medium of claim 9, wherein transforming 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, creating query language of the query configured to access a data repository specified by the location in the access method for the physical entity of the data.

13. The computer-readable medium of claim 9, wherein the access method types are selected from a group comprising an SQL query, an XML query and a procedural request.

14. 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 (a) 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

(b) access methods each defining a method for accessing the respective physical entity to be accessed, wherein each access method is of a given type according to a particular physical data representation of the data to be accessed; and

(iii) a runtime component for transforming the abstract query into a query consistent with the respective particular physical data representation of the physical entities of data according to the mapping rules, wherein transforming comprises partitioning the abstract query into sub-queries grouped according to the access method types; and

a processor adapted to execute contents of the memory.

15. The computer of claim 14, wherein a first portion of the data sources specified by the respective location specification are local and a second portion are remote.

16. The computer of claim 14, wherein the access method types are selected from a group comprising an SQL query, an XML query and a procedural request.