Database access system and method for transferring portions of an ordered record set responsive to multiple requests

• US 7,693,819 B2
• Filed: 12/29/2005
• Issued: 04/06/2010
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Stoychev, Mladen L.
• Primary Examiner(s): Alam; Hosain T
• Assistant Examiner(s): Tang; Jieying
• Application Number:
  US11/323,606
• Publication Number:
  US 20070156642A1
• Time in Patent Office: 1,559 Days
• Field of Search: 707/2, 707/7, 707/100, 707/10, 707/101, 707/102, 707/104.1, 709/201, 715/200
• US Class Current: 707/736
• CPC Class Codes: G06F 16/25 Integrating or interfacing systems involving database management systems

Abstract

Each record added to a database is assigned an identifier, for example, based on or at the time the record is added to the database. A database server receives a request for a first group of records that satisfy a condition, and searches and sorts on the basis of the identifier field all records in the database that satisfy the condition, to create an ordered set of records. The server sends the first group of records from the ordered set, in response to the request, and also sends a starting point in the ordered set from which to begin to send a second group of records from the ordered set that satisfy the condition.

Claims

1. In a database management system communicably interfaced with a database and a client, the database comprising a plurality of records, each record having a Unique Identifier (UID) assigned within the database, a method comprising:

receiving, from the client, a client records request comprising a filter, a page size, and a UID position (UIDp), the filter specifying one or more conditions that records returned to the client responsive to the client records request must satisfy, the page size specifying a user configurable quantity of records to be transferred to the client responsive to the client records request, and the UIDp specifying a maximum UID value assigned to a record within a first group of records previously sent to the client which also satisfies the one or more conditions of the filter;

creating an ordered record set comprising all records in the database satisfying the one or more conditions specified by the filter and sorted by the UID of each record;

selecting a second group of records from the ordered record set, wherein the second group of records begins with a record having a UID greater than the UIDp received from the client, and wherein the quantity of records within the second group of records corresponds to the page size; and

sending the second group of records to the client responsive to the client records request.

2. The method of claim 1, wherein the page size received from the client is based upon a quantity of records that can be readily displayed on a display device associated with the client.

3. The method of claim 1, further comprising:

receiving, from the client, a second client records request comprising the filter, the page size, and a second UIDp, wherein the second UIDp specifies a maximum UID value of a record within the second group of records previously sent to the client;

creating a new ordered record set comprising all records in the database satisfying the filter and sorted by the UID of each record;

selecting a third group of records from the new ordered record set beginning with a record having a UID greater than the second UIDp received from the client, and wherein the quantity of records within the third group of records corresponds to the page size; and

sending the third group of records to the client responsive to the second client records request.

4. The method of claim 1, further comprising:

adding a new record to the database having a UID greater than all records previously in the database or modifying an existing record within the database and reassigning a new UID to the existing record which is greater than all other records previously in the database, or both; and

updating the ordered record set after sending the second group of records to include all records in the database satisfying the one or more conditions specified by the filter, including the new record or the modified record, or both, and sorting the ordered record set by the UID of each record.

5. The method of claim 4, further comprising:

receiving, from the client, a second client records request comprising the filter, the page size, and a second UIDp, wherein the second UIDp specifies a maximum UID value assigned to a record within the second group of records previously sent to the client;

selecting, from the ordered record set previously updated, a third group of records beginning with a record having a UID greater than the second UIDp received from the client, and wherein the quantity of records within the third group of records corresponds to the page size; and

sending the third group of records to the client responsive to the second client records request.

6. The method of claim 1, wherein the UID assigned to each record within the database is based on a time associated with the addition of each record to the database or an order in which each record is added to the database.

7. The method of claim 1, wherein the client records request is made via a connectionless transfer protocol, and wherein the database management system cannot anticipate whether or when a subsequent client records request will be received.

8. The method of claim 1, further comprising:

receiving, from the client, a second client records request comprising the filter, the page size, and a UIDp First (UIDpFirst), wherein the UIDpFirst specifies a minimum UID value assigned to a record within the second group of records previously sent to the client;

creating a new ordered record set comprising all records in the database satisfying the filter and sorted by the UID of each record in descending order;

selecting a third group of records from the new ordered record set, wherein the first record of the third group of records has a UID less than the UIDpFirst, and wherein the quantity of records within the third group of records corresponds to the page size; and

sending the third group of records in descending order to the client responsive to the second client records request.

9. A machine-readable medium having instructions stored thereon that, when executed by a processor in a database management system, cause the database management system to perform a method comprising:

assigning a Unique Identifier (UID) to each of a plurality of records stored within a database communicably interfaced with the database management system;

receiving, from a client, a client records request comprising a filter and a UID position (UIDp), the filter specifying one or more conditions that records returned to the client responsive to the client records request must satisfy, and the UIDp specifying a maximum UID value assigned to a record within a first group of records previously sent to the client which also satisfies the one or more conditions of the filter;

creating an ordered record set comprising all records in the database satisfying the one or more conditions specified by the filter and sorted by the UID of each record;

selecting a second group of records from the ordered record set, wherein the second group of records begins with a record having a UID greater than the UIDp received from the client; and

sending the second group of records to the client responsive to the client records request.

10. The machine-readable medium of claim 9, wherein:

the client records request received from the client further comprises a page size specifying a user configurable quantity of records to be transferred to the client responsive to the client records request; and

wherein

selecting the second group of records from the ordered record set comprises limiting the quantity of records within the second group of records to the page size.

11. The machine-readable medium of claim 10, wherein the instructions cause the database management system to perform the method further comprising adding a new record to the database having a UID greater than all records previously in the database or modifying an existing record within the database and reassigning a new UID to the existing record which is greater than all other records previously in the database, or both.

12. The machine-readable medium of claim 11, wherein the instructions cause the database management system to perform the method further comprising:

receiving, from the client, a second client records request comprising the filter, the page size, and a second UIDp, wherein the second UIDp specifies a maximum UID value of a record within the second group of records previously sent to the client;

creating a new ordered record set comprising all records in the database satisfying the filter and sorted by the UID of each record;

selecting a third group of records from the new ordered record set beginning with a record having a UID greater than the second UIDp received from the client, and wherein the quantity of records within the third group of records corresponds to the page size; and

sending the third group of records to the client responsive to the second client records request.

13. The machine-readable medium of claim 9, wherein the client records request is made via a connectionless transfer protocol, and wherein the database management system cannot anticipate whether or when a subsequent client records request will be received.

14. The machine-readable medium of claim 10, wherein the instructions cause the database management system to perform the method further comprising:

receiving, from the client, a second client records request comprising the filter, the page size, and a UIDp First (UIDpFirst), wherein the UIDpFirst specifies a minimum UID value assigned to a record within the second group of records previously sent to the client;

creating a new ordered record set comprising all records in the database satisfying the filter and sorted by the UID of each record in descending order;

selecting a third group of records from the new ordered record set, wherein the first record of the third group of records has a UID less than the UIDpFirst, and wherein the quantity of records within the third group of records corresponds to the page size; and

sending the third group of records in descending order to the client responsive to the second client records request.

15. A database management system having a processor and memory therein and communicably interfaced between a database and a client, the database comprising a plurality of records, each record having a Unique Identifier (UID) assigned within the database, wherein the database management system comprises

means for receiving, from a client, a client records request comprising a filter and a UID position (UIDp), the filter specifying one or more conditions that records returned to the client responsive to the client records request must satisfy, and the UIDp specifying a maximum UID value assigned to a record within a first group of records previously sent to the client which also satisfies the one or more conditions of the filter;

means for creating an ordered record set comprising all records in the database satisfying the one or more conditions specified by the filter and sorted by the UID of each record;

means for selecting a second group of records from the ordered record set, wherein the second group of records begins with a record having a UID greater than the UIDp received from the client; and

means for sending the second group of records to the client responsive to the client records request.

16. The database management system of claim 15, wherein:

the client records request received from the client further comprises a page size specifying a user configurable quantity of records to be transferred to the client responsive to the client records request, the page size based upon a quantity of records that can be readily displayed on a display device associated with the client; and

wherein

selecting the second group of records from the ordered record set comprises means for limiting the quantity of records within the second group of records to the page size.

17. The database management system of claim 15, further comprising

means for adding a new record to the database having a UID greater than all records previously in the database or modifying an existing record within the database and means for reassigning a new UID to the existing record which is greater than all other records previously in the database, or means for both;

and

means for updating the ordered record set after sending the second group of records to include all records in the database satisfying the one or more conditions specified by the filter, including the new record or the modified record, or both, and sorting the ordered record set by the UID of each record.

18. The database management system of claim 17, further comprising:

means for receiving, from the client, a second client records request comprising the filter and a second UIDp, wherein the second UIDp specifies a maximum UID value of a record within the second group of records previously sent to the client;

means for selecting, from the ordered record set, a third group of records beginning with a record having a UID greater than the second UIDp received from the client; and

means for sending the third group of records to the client responsive to the second client records request, wherein the second client records request comprises a forward client records request for sequential records in ascending order.

19. The database management system of claim 18, further comprising:

means for sending a fourth group of records to the client responsive to a reverse client records request for previous records in descending order.

20. The database management system of claim 15, wherein the client records request is made via a connectionless transfer protocol, and wherein the database management system lacks means to anticipate whether or when a subsequent client records request will be received.