Field-to-field join constraints

• US 7,526,471 B2
• Filed: 12/17/2004
• Issued: 04/28/2009
• Est. Priority Date: 12/17/2004
• Status: Expired due to Fees

• Current Assignee: AirBNB Incorporated
• Original Assignee: International Business Machines Corporation
• Inventors: Kolz, Daniel P., Dettinger, Richard D., Stevens, Richard J.
• Primary Examiner(s): Fleurantin; Jean B
• Application Number:
  US11/016,215
• Publication Number:
  US 20060136470A1
• Time in Patent Office: 1,593 Days
• Field of Search: 707 1- 10, 707100-1041, 707200-206
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2471 Distributed queries
• CPC Class Codes: G06F 16/258 Data format conversion from or to a database
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

Embodiments of the present invention generally provide methods systems and articles of manufacture for query processing and for constructing a database abstraction model over an underlying physical database. The database abstraction model allows users to compose an abstract query using a logical view of data, instead of using the view of the underlying database architecture. Embodiments of the invention constrain the results returned from processing an abstract query according to relationships that exist for a group of logical fields. First, a group of logical fields may be related because they are part of a logical set. Field-to-field join constraints specify the logical fields that form a set, and an instance indicator used to determine the particular instance of a set that an element of data belongs to, according to a discrimination rule. Second, logical fields may be related because they are part of a series, and an instance identifier may provide an ordering rule used to determine the order of data elements that form the series.

Claims

1. A computer-implemented method of creating a database abstraction model, comprising, by operation of a least one processor:

defining a database abstraction model, wherein the database abstraction model defines a plurality of logical fields for composing abstract queries via an interface, wherein each logical field specifies (i) a name for the logical field and (ii) at least an access method that maps the logical field to data in an underlying physical database;

defining, for the database abstraction model, a field-to-field join constraint based on an identified logical relationship for a group of logical fields, wherein the field-to-field join constraint defines how a set of query results retrieved for the group of logical fields should be joined together for purposes of being output;

wherein an abstract query composed via the interface and including the group of logical fields is a format suitable to be transformed by a runtime component into a resolved query of the database; and

storing the database abstraction model and the field-to-field join constraint on a computer readable storage medium.

2. The method of claim 1, wherein the set of query results are grouped into one of (i) instances of a set, wherein the field-to-field join constraint includes an instance indicator used to determine into which instance of a set an element of data included in the query results is placed or (ii) an ordered series, wherein an instance identifier is used to determine the order, relative to the series, of an element of data from the query results.

3. The method of claim 2, wherein the series is time-ordered.

4. The method of claim 1, further comprising, providing (i) the interface for composing an abstract query that includes the group of logical fields and (ii) the runtime component configured to generate, from the abstract query, the resolved query of the database.

5. The method of claim 4, wherein the interface is further configured to allow a user to specify an additional field-to-field join constraint for a group of logical fields.

6. A computer-implemented method of processing an abstract query that includes a group of logical fields specified by a field-to-field join constraint, comprising, by operation of a least one processor:

receiving, the abstract query from a requesting entity having an interface in which the abstract query was composed, wherein the abstract query is composed from a plurality of logical fields specified in a database abstraction model, and wherein each logical field defines at least an access method that maps the logical field to data in an underlying physical database;

generating, from the abstract query, a resolved query of the underlying physical database;

the generating being performed by a runtime component;

issuing the resolved query to the underlying physical database to retrieve a set of query results;

grouping the query results according to the field-to-field join constraint, wherein the field-to-field join constraint specifies how query results retrieved for the group of logical fields should be joined together for purposes of being output; and

returning the grouped query results to the requesting entity.

7. The method of claim 6, wherein the set of query results are grouped into one of (i) instances of a set, wherein the field-to-field join constraint includes an instance indicator used to determine which instance of a set that an element of data included in the query results is placed or (ii) an ordered series, wherein an instance identifier is used to determine the order, relative to the series, of an element of data from the query results.

8. The method of claim 7, wherein the series is time-ordered.

9. The method of claim 6, wherein the interface is further configured to allow a user to specify an additional field-to-field join constraint for a group of logical fields.

10. A computer-implemented method of processing an abstract query that includes a group of logical fields specified by a field-to-field join constraint, comprising, by operation of a least one processor:

receiving, the abstract query from a requesting entity having an interface in which the abstract query was composed, wherein the abstract query is composed from a plurality of logical fields specified in a database abstraction model, and wherein each logical field defines at least an access method that maps the logical field to data in an underlying physical database;

generating, from the abstract query, a resolved query of the underlying physical database;

the generating being performed by a runtime component;

modifying the resolved query according to the field-to-field join constraint, wherein the field-to-field join constraint defines how the set of query results retrieved for the group of logical fields should be joined together for purposes of being output;

executing the resolved query to retrieve a set of grouped query results from the database; and

returning the grouped query results to the requesting entity.

11. The method of claim 10, wherein the set of query results are grouped into one of (i) instances of a set, wherein the field-to-field join constraint includes an instance indicator used to determine which instance of a set that an element of data included in the query results is placed or (ii) an ordered series, wherein an instance identifier is used to determine the order, relative to the series, of an element of data from the query results.

12. The method of claim 11, wherein the series is time-ordered.

13. The method of claim 12, wherein the interface is further configured to allow a user to specify an additional field-to-field join constraint for a group of logical fields.