Sequence support operators for an abstract database

• US 8,095,553 B2
• Filed: 03/17/2005
• Issued: 01/10/2012
• Est. Priority Date: 03/17/2005
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Dettinger, Richard D., Kolz, Daniel P.
• Primary Examiner(s): Timblin, Robert
• Assistant Examiner(s): Reyes, Mariela D
• Application Number:
  US11/083,208
• Publication Number:
  US 20060212418A1
• Time in Patent Office: 2,490 Days
• Field of Search: 707/758, 707/759, 707/763, 707/805
• US Class Current: 707/759
• 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 computer-implemented 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 define;

(i) a logical field name, (ii) an access method selected from at least two different access method types and (iii) a location in the physical database for accessing respective data elements in the physical database;

wherein at least a first logical field further defines how to order data elements accessed for the at least one logical field, wherein the location defined by the first logical field comprises a first physical field of the physical database, wherein the first logical field defines that the data elements accessed for the first logical field are ordered based on at least one of;

(i) a second logical field of the plurality of logical fields of the database abstraction model and (ii) a second physical field of the physical database;

providing a query building interface for composing an abstract query from the plurality of logical fields in the database abstraction model, wherein the abstract query specifies which of the data elements should be retrieved based on their respective order positions without specifying how to order the data elements, the data elements being ordered as defined by the first logical field; and

providing a runtime component configured to generate, from the abstract query and by operation of one or more computer processors, a resolved query executable against the physical database, wherein the resolved query is configured to retrieve the data elements specified by the abstract query and ordered as defined by the first logical field of the database abstraction model.

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

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

4. The method of claim 1, wherein the order positions include at least one of:

an order position of a single data element, from the data elements which are ordered as defined by the first logical field, to be retrieved for the abstract query; and

order positions of a range of data elements, from the data elements which are ordered as defined by the first logical field, to be retrieved for the abstract query.

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

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. The method of claim 1, wherein at least one of the logical fields has no corresponding physical field in any physical table in the physical database and the respective access method for the at least one of the logical fields calculates a value.

9. The method of claim 1, whereby the data elements are accessed from the physical database, ordered based on the database abstraction model, and selected based on the abstract query.

10. The method of claim 1, whereby the data elements are accessed from the physical database, ordered based on the database abstraction model and not based on the abstract query, and selected based on at least one of the database abstraction model and the abstract query.

11. The method of claim 1, whereby logic that orders and selects the data elements is divided between the database abstraction model and the abstract query.

12. A computer-implemented method of accessing physical data having a particular physical data representation, comprising configuring one or more computer processors to perform an operation 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 the database abstraction model, wherein the database abstraction model defines a plurality of logical field definitions mapping logical fields to the physical data, 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, wherein the logical field definition for at least a first logical field defines how to order physical data elements corresponding to the first logical field, wherein the location defined by the first logical field comprises a first physical field of a physical database storing the physical data, wherein the first logical field defines that the data elements accessed for the first logical field are ordered based on at least one of;

(i) a second logical field of the plurality of logical fields of the database abstraction model and (ii) a second physical field of the physical database, and wherein the abstract query is composed on the basis of the plurality of logical field definitions; and

transforming, by operation of the one or more computer processors, the abstract query into a query consistent with the particular physical data representation according to the database abstraction model depending on which of the plurality of logical fields definitions are referenced by the abstract query, wherein the abstract query specifies which of the physical data elements should be retrieved based on their respective order positions without specifying how to order the physical data elements, the physical elements being ordered as defined by the first logical field.

13. The method of claim 12, 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.

14. The method of claim 12, wherein a first access method type comprises 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.

15. The method of claim 12, wherein a first access method type comprises 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.

16. The method of claim 12, wherein the first logical field indicates that the physical data corresponding to the at least one logical field are to be sequenced according to a chronological order.

17. The method of claim 12, wherein the first logical field indicates the physical data corresponding to the first logical field are to be sequenced according to the relative magnitude of the physical data elements.

18. The method of claim 12, wherein specifying the order positions include at least one of:

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

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

19. The method of claim 12, wherein the abstract query further specifies that a condition included in the abstract query should only be evaluated against the data elements specified by the abstract query.

20. The method of claim 12, wherein at least one of the logical fields has no corresponding physical field in any physical table in the physical database and the respective access method for the at least one of the logical fields calculates a value.

21. The method of claim 12, whereby the data elements are:

(i) accessed from a physical database storing the physical data;

(ii) ordered based on the database abstraction model; and

(iii) selected based on the abstract query.

22. The method of claim 12, whereby the data elements are accessed from a physical database storing the physical data;

(ii) ordered based on the database abstraction model and not based on the abstract query; and

(iii) selected based on at least one of the database abstraction model and the abstract query.

23. The method of claim 12, whereby logic that orders and selects the data elements is divided between the database abstraction model and the abstract query.