Sequence support operators for an abstract database

• US 20060212418A1
• Filed: 03/17/2005
• Published: 09/21/2006
• Est. Priority Date: 03/17/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kolz, Daniel P., Dettinger, Richard D.
• Granted Patent: US 8,095,553 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2428 Query predicate definition using graphical user interfaces, including menus and forms G06F16/2423 takes precedence

Abstract

The present invention generally provides methods, systems and articles of manufacture that provide a database query application that allows user to compose an abstract query that includes a sequence operator. In one embodiment, sequence operators are used to specify which data elements, from a sequence of data elements, should be retrieved for an abstract query. In another embodiment, a sequence operator may be used to specify that a condition included in an abstract query should be evaluated against particular data elements of the sequence.

Claims

1. A method of providing access to data in a physical database, comprising:

providing a database abstraction model that defines a plurality of logical fields that each provide an access method for accessing data elements in the physical database, wherein at least one logical field further provides, metadata indicating a data value used to order the data elements, accessed for the at least one logical field, into an ordered sequence;

providing a query building interface for composing an abstract query from the plurality of logical fields, wherein the abstract query includes a sequence operator for specifying which data elements, from the ordered sequence, should be retrieved for the abstract query; and

providing a runtime component configured to generate, from the abstract query, a resolved query executable against the physical database, wherein the resolved query is configured to retrieve the specified data elements from the ordered sequence.

2. The method of claim 1, wherein the data value indicates that data elements accessed for the at least one logical field should be sequenced according to a chronological order.

3. The method of claim 1, wherein the data value indicates that the data elements accessed for the at least one logical field should be sequenced according to the relative magnitude of the data elements.

4. The method of claim 1, wherein the sequence operator specifies at least one of:

a single data element, from the ordered sequence, to be retrieved for the abstract query; and

a range of data elements, from the ordered sequence, to be retrieved for the abstract query.

5. The method of claim 1, wherein the sequence operator further specifies that a condition included in the abstract query should only be evaluated against the data elements retrieved from the sequence of data elements.

6. The method of claim 1, wherein the database abstraction model further defines a model entity, wherein the model entity is used as the logical focus of an abstract query, and wherein an identifier in the physical database is used to distinguish instances of the model entity.

7. The method of claim 6, wherein the identifier for the model entity comprises, a primary key column from a table in a relational database, and wherein instances of the model entity may be identified by entries from the primary key column.

8. A computer-readable medium, containing a program which, when executed on a processor performs operations for providing access to data in a database, comprising:

providing a database abstraction model that defines a plurality of logical fields that each provide an access method for accessing data elements in the physical database, wherein at least one logical field further provides, metadata indicating a data value used to order the data elements, accessed for the at least one logical field, into an ordered sequence;

providing a query building interface for composing an abstract query from the plurality of logical fields, wherein the abstract query includes a sequence operator for specifying which data elements, from the ordered sequence, should be retrieved for the abstract query; and

providing a runtime component configured to generate, from the abstract query, a resolved query executable against the physical database, wherein the resolved query is configured to retrieve the specified data elements from the ordered sequence.

9. The computer-readable medium of claim 8, wherein the data value indicates that data elements accessed for the at least one logical field should be sequenced according to a chronological order.

10. The computer-readable medium of claim 8, wherein the data value indicates that the data elements accessed for the at least one logical field should be sequenced according to the relative magnitude of the data elements.

11. The computer-readable medium of claim 8, wherein the sequence operator specifies at least one of:

a single data element, from the ordered sequence, to be retrieved for the abstract query; and

a range of data elements, from the ordered sequence, to be retrieved for the abstract query.

12. The computer-readable medium of claim 8, wherein the sequence operator further specifies that a condition included in the abstract query should only be evaluated against the data elements retrieved from the sequence of data elements.

13. The computer-readable medium of claim 8, wherein the database abstraction model further defines a model entity, wherein the model entity is used as the logical focus of an abstract query, and wherein an identifier in the physical database is used to distinguish instances of the model entity.

14. The computer-readable medium of claim 13, wherein the identifier for the model entity comprises, a primary key column from a table in a relational database, and wherein instances of the model entity may be identified by entries from the primary key column.

15. A system, comprising;

a physical database;

a database abstraction model that defines a plurality of logical fields that each provide an access method for accessing data elements in the physical database, wherein at least one logical field further provides, metadata indicating a data value used to order the data elements, accessed for the at least one logical field, into an ordered sequence;

a query building interface for composing an abstract query from the plurality of logical fields, wherein the abstract query includes a sequence operator for specifying which data elements, from the ordered sequence, that should be retrieved for the abstract query; and

a runtime component configured to generate, from the abstract query, a resolved query executable against the physical database, wherein the resolved query is configured to retrieve the specified data elements from the ordered sequence.

16. The system of claim 15, wherein the sequence operator specifies at least one of:

a single data element, from the ordered sequence, to be retrieved for the abstract query; and

a range of data elements from the ordered sequence, to be retrieved for the abstract query.

17. The system of claim 16, wherein the identifier for the model entity comprises, a primary key column from a table in a relational database, and wherein instances of the model entity may be identified by entries from the primary key column.

18. A computer-implemented method of accessing physical data having a particular physical data representation, comprising:

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

wherein the query specification defines an interface to a data abstraction model defining a plurality of logical field definitions mapping logical fields to the physical data, wherein the logical field definition for at least one logical field includes metadata indicating a value for ordering the physical data corresponding to the at least one logical field into an ordered sequence of physical data elements, and wherein the abstract query is composed on the basis of the plurality of logical field definitions; and

transforming the abstract query into a query consistent with the particular physical data representation according to the data abstraction model depending on which of the plurality of logical fields definitions are referenced by the abstract query, wherein each of the logical field definitions comprises 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 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.

19. The method of claim 18, wherein a first access method type is a simple access method defining a direct relationship between physical data located at a location identified by a respective location attribute of a respective logical field definition;

and wherein a second access method type is a filtered access method defining a filter applied to physical data located at a location identified by a respective location attribute of a respective logical field definition, wherein the filter removes selected data from the physical data so that only a subset of the physical data is exposed by the respective logical field definition referencing the filtered access method.

20. The method of claim 18, wherein the access methods types comprise a filtered access method defining a filter applied to physical data located at a location identified by a respective location attribute of a respective logical field definition, wherein the filter removes selected data from the physical data so that only a subset of the physical data is exposed by the respective logical field definition referencing the filtered access method.

21. The method of claim 18, wherein the access methods types comprise a composed access method defining an expression applied to physical data located at a location identified by a respective location attribute of a respective logical field definition, wherein application of the expression produces values different from the physical data to which the expression is applied.

22. The method of claim 18, wherein the metadata indicates that the physical data corresponding to the at least one logical field should be sequenced according to a chronological order.

23. The method of claim 18, wherein metadata indicates the physical data corresponding to the at least one logical field should be sequenced according to the relative magnitude of the physical data elements.

24. The method of claim 18, wherein the sequence operator specifies at least one of:

a single physical data element, from the ordered sequence, to be retrieved for the abstract query; and

a range of physical data elements, from the ordered sequence, to be retrieved for the abstract query.

25. The method of claim 18, wherein the sequence operator further specifies that a condition included in the abstract query should only be evaluated against the data elements retrieved from the sequence of data elements.