Application portability and extensibility through database schema and query abstraction

• US 20060010127A1
• Filed: 09/14/2005
• Published: 01/12/2006
• Est. Priority Date: 02/26/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Stevens, Richard Joseph, Dettinger, Richard Dean, Johnson, Peter John, Will, Eric, Tong, Ikhua
• Granted Patent: US 8,180,787 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2423 Interactive query statement specification based on a database schema
• CPC Class Codes: G06F 16/2428 Query predicate definition using graphical user interfaces, including menus and forms G06F16/2423 takes precedence
• CPC Class Codes: Y10S 707/99934 Query formulation, input preparation, or translation
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

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. 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 having a particular schema, comprising:

in response to receiving an abstract query, accessing a data abstraction model which models the data having the particular schema and exposes the data to users in a manner that allows the users to compose queries on the basis of the data abstraction model without knowledge or regard for the particular schema;

wherein the model comprises a plurality of logical field definitions, each of the definitions comprising a logical field name, at least one location attribute identifying a location of physical data corresponding to the logical field name, and a reference to an access method invoked to access the physical data in response to receiving the abstract query containing the logical field name;

wherein at least one of the logical field names is different from a physical field name of the corresponding physical data as defined by the schema.

2. The method of claim 1, receiving logical field selection input to a query composition application that defines an interface to the plurality of logical field definitions of the abstraction model, thereby allowing abstract queries to be composed on the basis of the plurality of logical field definitions.

3. The method of claim 1, wherein the abstract query comprises (i) at least one a result specification specifying one or more logical field definitions for which results are to be returned and (ii) at least one selection criterion specifying conditions to filter the physical data corresponding to the one or more logical field definitions specified by the result specification.

4. The method of claim 1, further comprising transforming the abstract query into a query consistent with the particular schema;

the transforming being done on the basis of those logical field definitions of the data abstraction model that correspond to field names contained in the abstract query.

5. The method of claim 1, wherein each access method is selected from at least two different access method types;

wherein each of the different access methods types defines a different manner of exposing the physical data corresponding to the logical field name of the respective logical field definition.

6. The method of claim 1, wherein the different access methods types include at least a composed access method type;

wherein composed access methods, of respective logical field definitions, define an expression for the respective logical definitions, the expression being defined on the basis of a different logical field definition.

7. The method of claim 1, wherein the different access methods types include at least a simple access method type and a filtered access method type;

wherein simple access methods map a corresponding logical field name directly to a particular physical data field of the physical data, and wherein filtered access methods map a corresponding logical field name to a subset of physical data corresponding to a particular physical data field of the physical data.

8. The method of claim 1, wherein the different access methods types include at least a simple access method type and a composed access method type;

wherein simple access methods map a corresponding logical field name, of a respective logical field definition, directly to a particular physical data field of the physical data; and

wherein composed access methods, of respective logical field definitions, define an expression for the respective logical definitions, the expression being defined on the basis of a different logical field definition.

9. The method of claim 1, further comprising transforming the abstract query into a query consistent with the particular schema;

the transforming including generating query logic not explicitly defined by user selections made in composing the abstract query on the basis of the abstraction model.

10. The method of claim 9, where the query consistent with the particular schema is one of a SQL query and an XML query.

11. A computer-implemented method of providing access to data having a particular schema, comprising:

receiving abstract queries composed on the basis of a data abstraction model which models the data having the particular schema and exposes the data to users in a manner that allows the users to compose queries on the basis of the data abstraction model without knowledge or regard for the particular schema;

wherein the model comprises a plurality of logical field definitions, each of the definitions comprising a logical field name, at least one location attribute identifying a location of physical data corresponding to the logical field name, and a reference to an access method invoked to access the physical data in response to receiving the abstract query containing the logical field name;

wherein at least one of the logical field names is different from a physical field name of the corresponding physical data as defined by the schema;

;

in response to receiving each abstract query;

accessing those logical field definitions of the data abstraction model that correspond to logical field names included in the abstract query;

on the basis accessed logical field definitions, transforming the abstract query into an executable query consistent with the particular schema; and

providing the executable query to a query execution environment for execution.

12. The method of claim 11, wherein the transforming includes generating query logic not explicitly defined by user selections made in composing the abstract query on the basis of the abstraction model.

13. The method of claim 11, wherein each access method is selected from at least two different access method types;

wherein each of the different access methods types defines a different manner of exposing the physical data corresponding to the logical field name of the respective logical field definition.

14. The method of claim 11, wherein the different access methods types include at least a composed access method type;

wherein composed access methods, of respective logical field definitions, define an expression for the respective logical definitions, the expression being defined on the basis of a different logical field definition.

15. The method of claim 11, wherein the different access methods types include at least a simple access method type and a filtered access method type;

wherein simple access methods map a corresponding logical field name directly to a particular physical data field of the physical data, and wherein filtered access methods map a corresponding logical field name to a subset of physical data corresponding to a particular physical data field of the physical data.

16. The method of claim 11, wherein the different access methods types include at least a simple access method type and a composed access method type;

wherein simple access methods map a corresponding logical field name, of a respective logical field definition, directly to a particular physical data field of the physical data; and

wherein composed access methods, of respective logical field definitions, define an expression for the respective logical definitions, the expression being defined on the basis of a different logical field definition.

17. A computer-readable medium containing a program which, when executed by a processor, performs an operation of generating executable queries configured to access to data having a particular schema, the operation comprising:

transforming abstract queries into executable queries, the abstract queries having been composed on the basis of a data abstraction model which models the data having the particular schema and exposes the data to users in a manner that allows the users to compose queries on the basis of the data abstraction model without knowledge or regard for the particular schema;

wherein the model comprises a plurality of logical field definitions, each of the definitions comprising a logical field name, at least one location attribute identifying a location of physical data corresponding to the logical field name, and a reference to an access method invoked to access the physical data in response to receiving the abstract query containing the logical field name;

wherein at least one of the logical field names is different from a physical field name of the corresponding physical data as defined by the schema;

wherein transforming comprises;

accessing those logical field definitions of the data abstraction model that correspond to logical field names included in the abstract query;

generating query conditions on the basis of the accessed logical field definitions.

18. The computer-readable medium of claim 17, further comprising providing the executable query to a query execution environment for execution.

19. The computer-readable medium of claim 17, wherein each access method is selected from at least two different access method types;

wherein each of the different access methods types defines a different manner of exposing the physical data corresponding to the logical field name of the respective logical field definition.

20. The computer-readable medium of claim 17, wherein at least some of the executable queries are transformed into SQL queries and at least some of the executable queries are transformed into non-SQL queries.