ABSTRACT QUERY PLAN

• US 20080091668A1
• Filed: 12/11/2007
• Published: 04/17/2008
• Est. Priority Date: 12/06/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: DETTINGER, RICHARD, Kolz, Daniel
• Granted Patent: US 8,886,632 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/24526 Internal representations for queries
• CPC Class Codes: G06F 16/24549 Run-time optimisation
• 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
• CPC Class Codes: Y10S 707/99935 Query augmenting and refining, e.g. inexact access
• CPC Class Codes: Y10S 707/99936 Pattern matching access

Abstract

A method and apparatus, and article of manufacture are provided to process an abstract query of a database abstraction constructed over an underlying physical data storage mechanism. The database may comprise a single data source, or a federated source spanning multiple systems. Embodiments of the invention process an abstract query by generating an intermediate representation of the abstract query. In one embodiment, the intermediate representation comprises an abstract query plan. An abstract query plan includes a combination of elements from the data abstraction model and elements relating to the underlying physical data storage mechanism. Once generated, a back-end component may easily traverse the abstract query plan to generate an SQL statement (or other resolved query) corresponding to the abstract query. Further, once constructed, the abstract query plan provides a platform for many different optimizations that may be selected by a user or by the runtime component inspecting the abstract query plan prior to creating the resolved query.

Claims

1. A method of providing an abstraction of a relational database, comprising:

defining a data abstraction model, wherein the data abstraction model comprises;

(i) a plurality of logical fields, wherein each logical field identifies a name for the logical field and an access method that maps the logical field to a column of a table in the relational database, (ii) an indication of the relationships between logical fields, and a (iii) a representation of the relational database that identifies the relationships between data sources in the relational database;

providing a query building interface configured to allow a user to compose an abstract query from the plurality of logical fields; and

providing a runtime component configured to process an abstract query to generate an intermediate representation of the abstract query.

2. The method of claim 1, wherein the intermediate representation of the abstract query comprises an abstract query plan, wherein the abstract query plan comprises (i) a plurality of table instances, wherein the each table instance includes an indication of a data source, each of the logical fields included in the abstract query that depend on data present on the indicated data source, and conditions used to limit the data selected from the indicated data source;

and (ii) a set of join relationships that indicate how the plurality of table instances are related to one another relative to the abstract query; and

(iii) a set of join relationships that indicate how the plurality of table instances are related to one another relative to the abstract query.

3. The method of claim 1, further comprising, presenting a user with an indication of the abstract query plan and allowing the user to optimize the intermediate representation by (i) modifying the set of join relationships or (ii) reducing a number of identical table instances included in the abstract query plan.

4. The method of claim 3, wherein presenting the user with an indication of the intermediate representation comprises generating displaying a graphical representation of the interface that illustrates each table instance and set of join relationships between the table instances.

5. The method of claim 2, wherein the runtime component is further configured to generate, from the abstract query plan, a resolved query of the relational database comprising an SQL statement.

6. The method of claim 1, wherein the representation of the relational database comprises a graph representation wherein each node represents a data source, and each edge represents a relationship between data sources.

7. The method of claim 1, wherein the query building interface comprises a web-based interface.

8. The method of claim 1, wherein the database comprises a federated database defined using a relational schema constructed from a plurality of individual relational databases.

9. The method of claim 1, wherein the access method for each logical field is selected from one of a simple, filtered, or composed access method.

10. A computer-readable storage medium containing a plurality of instructions which, when executed on a computer system is configured to perform operations comprising:

defining a data abstraction model, wherein the data abstraction model comprises;

a plurality of logical fields, wherein each logical field identifies a name for the logical field and an access method that maps the logical field to a data source in a relational database, an indication of the relationships between logical fields, and a graph representation of the relational database that identifies the relationships between data sources in the relational database; and

providing a query building interface configured to allow the composition of an abstract query from the plurality of logical fields;

providing a runtime component configured to process an abstract query to generate an intermediate representation of the abstract query.

11. The computer-readable storage medium of claim 10, wherein the intermediate representation of the abstract query comprises an abstract query plan, wherein the abstract query plan comprises (i) a plurality of table instances, wherein the each table instance includes an indication of a data source, each of the logical fields included in the abstract query that depend on data present on the indicated data source, and conditions used to limit the data selected from the indicated data source;

and (ii) a set of join relationships that indicate how the plurality of table instances are related to one another relative to the abstract query; and

(iii) a set of join relationships that indicate how the plurality of table instances are related to one another relative to the abstract query.

12. The computer-readable storage medium of claim 10, further comprising, presenting a user with an indication of the abstract query plan and allowing the user to optimize the intermediate representation by (i) modifying the set of join relationships or (ii) reducing a number of identical table instances included in the abstract query plan.

13. The computer-readable storage medium of claim 12, wherein presenting the user with an indication of the intermediate representation comprises generating displaying a graphical representation of the interface that illustrates each table instance and set of join relationships between the table instances.

14. The computer-readable storage medium of claim 11 wherein the runtime component is further configured to generate, from the abstract query plan, a resolved query of the relational database comprising an SQL statement.

15. The computer-readable storage medium of claim 10, wherein the graph representation comprises a plurality of nodes, wherein each node represents a data source, and each edge represents a relationship between data sources.

16. The computer-readable storage medium of claim 10, wherein the query building interface comprises a web-based interface.

17. The computer-readable storage medium of claim 10, wherein the database comprises a federated database defined using a relational schema constructed from a plurality of individual relational databases.

18. The computer-readable storage medium of claim 10, wherein the access method for each logical field is selected from one of a simple, filtered, or composed access method.