Efficient calculation of sets of distinct results

• US 20070185838A1
• Filed: 05/15/2006
• Published: 08/09/2007
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Peh, Thomas, Schwedes, Holger, Stephan, Wolfgang, Steinau, Oliver
• Granted Patent: US 8,027,969 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/24537 of operators
• CPC Class Codes: G06F 16/24556 Aggregation; Duplicate elimination
• CPC Class Codes: G06F 16/2456 Join operations
• CPC Class Codes: G06F 16/951 Indexing; Web crawling techniques
• CPC Class Codes: G06Q 10/00 Administration; Management
• CPC Class Codes: Y10S 707/99931 Database or file accessing

Abstract

Systems and methods are provided for efficient calculation of sets of distinct results in an information retrieval service. A query is received having at least one requested attribute and one or more conditions. For each row identifier in a database table that matches the one or more conditions, a tuple of value identifiers having an entry for each requested attribute is calculated. A unique number is generated and assigned to the tuple for each distinct combination of the value identifiers. Duplicate entries in the tuple listing are identified and removed, so that a result set provides only distinct results.

Claims

1. A computer-implemented method for efficient calculation of sets of distinct results in an information retrieval service, the method comprising:

receiving a query from a client application, the query having at least one requested attribute and one or more conditions;

for each row identifier in a database table that matches the one or more conditions, calculating a tuple of value identifiers having an entry for each requested attribute; and

assigning a unique number to the tuple for each distinct combination of the value identifiers.

2. A method in accordance with claim 1, further comprising generating a list of the row identifiers mapped with the unique numbers.

3. A method in accordance with claim 2, further comprising determining, from the list or the row identifiers mapped with the unique numbers, duplicate list entries based on the attributes requested in the query.

4. A method in accordance with claim 3, further comprising deleting duplicate entries from the list to isolate for each unique number a single remaining tuple.

5. A method in accordance with claim 4, further comprising inserting the remaining tuple into a result set.

6. A method in accordance with claim 5, further comprising returning the result set to the client application.

7. A method in accordance with claim 1, wherein the one or more conditions include a SELECT condition and a JOIN condition.

8. A computer-readable storage medium containing a set of instructions for an information retrieval computer, the set of instructions causing the information retrieval computer to:

receive a query from a client application, the query having at least one requested attribute and one or more conditions;

for each row identifier in a database table that matches the one or more conditions, calculate a tuple of value identifiers having an entry for each requested attribute; and

assign a unique number to the tuple for each distinct combination of the value identifiers.

9. A computer-readable storage medium in accordance with claim 8, wherein the set of instructions further causes the information retrieval computer to generate a list of the row identifiers mapped with the unique numbers.

10. A computer-readable storage medium in accordance with claim 9, wherein the set of instructions further causes the information retrieval computer to determine, from the list or the row identifiers mapped with the unique numbers, duplicate list entries based on the attributes specified in the query.

11. A computer-readable storage medium in accordance with claim 10, wherein the set of instructions further causes the information retrieval computer to delete duplicate list entries from the list to generate a remaining tuple.

12. A computer-readable storage medium in accordance with claim 11, wherein the set of instructions further causes the information retrieval computer to insert the remaining tuple into a result set.

13. A computer-readable storage medium in accordance with claim 12, wherein the set of instructions further causes the information retrieval computer to return the result set to the client application.

14. A computer-readable storage medium in accordance with claim 13, wherein the set of instructions further causes the information retrieval computer to process SELECT and JOIN conditions.

15. A system for efficient calculation of sets of distinct results in an information retrieval service, the system comprising:

a name server for receiving a query from a client application, the query having at least one requested attribute and one or more conditions; and

an attribute engine for parsing the query to execute the one or more conditions to search the at least one requested attribute, the attribute engine further being configured to;

for each row identifier in a database table that matches the one or more conditions, calculate a tuple of value identifiers having an entry for each requested attribute; and

assign a unique number to the tuple for each distinct combination of the value identifiers.

16. A system in accordance with claim 15, wherein the attribute engine is further configured to generate a list of the row identifiers mapped with the unique numbers.

17. A system in accordance with claim 16, wherein the attribute engine is further configured to determine, from the list or the row identifiers mapped with the unique numbers, duplicate list entries based on the attributes specified in the query.

18. A system in accordance with claim 17, wherein the attribute engine is further configured to delete duplicate list entries from the list to generate a remaining tuple.

19. A system in accordance with claim 18, wherein the attribute engine is further configured to insert the remaining tuple into a result set.

20. A system in accordance with claim 19, further comprising a queue server for storing the result set and providing access to the result set to the client application.