Data change notifications

• US 20070050392A1
• Filed: 08/25/2005
• Published: 03/01/2007
• Est. Priority Date: 08/25/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Klein, Johannes, Shukla, Amit, Acharya, Srinivasmurthy, Fang, Lijiang, Singh, Siddhartha, Yuan, Hua, Luo, Chang, Ryseff, James, Ellis, Nigel
• Granted Patent: US 7,543,003 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2358 Change logging, detection, and notification replication G06F16/27
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99939 Privileged access
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A framework for data change notification includes a notification queue storing event notifications. Client applications can request event information regarding various data change events. For example, a client application can subscribe, via one or more APIs, to receive event information. The framework allows for session specific event notification mechanisms as well as durable event notification mechanisms that can be preserved across client sessions as well as server restarts. Innovative aspects of this invention include guaranteed delivery of event notifications, APIs to allow applications get summary of past events on the subscribed objects, automatic garbage collection/cleanup of notifications when a client session terminates.

Claims

1. A method for providing change notifications to an entity regarding a change of a specific type to data in a relational database, said method comprising:

receiving entity information identifying said entity;

receiving change information regarding said specific type of change; and

providing change notification data to said entity regarding a change in said relational database of said specific type.

2. The method of claim 1, where said step of providing change notification data to said entity comprises:

storing said change notification data in a queue.

3. The method of claim 2, where said step of providing change notification data to said entity comprises:

responding to a request for data from said queue.

4. The method of claim 3, where said step of responding to a request for data from said queue comprises:

responding to a wait-for query executed on said queue.

5. The method of claim 2, where said step of responding to a request for data from said queue comprises:

determining using entity information whether said request issued from said entity.

6. The method of claim 1, where said change is involves a specific item in said relational database, where access to said specific item in said relational database is limited by a security requirement, said method further comprising:

determining that said entity fulfills said security requirement.

7. The method of claim 2, where said queue comprises additional change notification information items, each of said additional change notification information items corresponding to a requesting entity, said method further comprising:

if a connection to said entity is terminated, deleting any of said additional change notification information in said queue corresponding to said entity.

8. The method of claim 2, where said queue comprises additional change notification information items, each of said additional change notification information items corresponding to a requesting entity, said method further comprising:

determining that a connection to said entity is terminated;

determining that a new connection so said entity exists; and

providing said additional change notification information items corresponding to said requesting entity using said new connection.

9. A system for providing to an entity at least one change notification, each change notification regarding a change in a database, said system comprising:

subscription table storage storing entity information regarding said entity and change information regarding at least one change definition, said change definition defining one or more possible changes to said database;

a notification dispatcher, said notification dispatcher operatively connected to said subscription table, said notification dispatcher operatively connected to said database, and said notification dispatcher querying said database for database changes pertaining to said change definitions and receiving data regarding a pertinent change; and

a notifier, operatively connected to said notification dispatcher, said notifier operatively connected to said entity, said notifier providing at least one notification regarding said pertinent change.

10. The system of claim 9, where said notifier comprises:

a queue storing at least one of said at least one notification regarding said pertinent change.

11. The system of claim 10, where said queue receives queries from said entity and where said provision of at least one notification regarding said pertinent change is in response to said query.

12. The system of claim 10, further comprising:

a service broker, said service broker, if said operative connection between said notifier and said entity is terminated, removing all pertinent changes corresponding to said entity from said queue.

13. A computer-readable medium comprising computer-executable instructions, said computer-executable instructions for performing the steps of:

querying a database for information regarding a data change corresponding to at least one change definition, each of said at least one change definitions corresponding to a requesting entity from among a set of possible requesting entities; and

providing data change data regarding said data change to one of said requesting entities.

14. The computer-readable medium of claim 13, said step of providing data change data regarding said data change further comprising:

for each of said requesting entities, storing a notification data item in a queue, said notification data item comprising said data change data and an entity identifier corresponding to said requesting entity;

responding to a request for data from said queue from one of said requesting entities with at least one responsive notification data item from among said notification data items in said queue, where each of said responsive notification data items comprising an entity identifier corresponding to said one of said requesting entities.

15. The computer-readable medium of claim 14, where said notification data further comprises time data identifying a point in time, where said request for data comprises a range of time, and where said time data for each of said responsive notification data items is contained in said range.

16. The computer-readable medium of claim 14, where said request is a wait-for request on said queue.

17. The computer readable medium of claim 13, further comprising:

providing a method for an entity to register as one of said possible requesting entities.

18. The computer readable medium of claim 13, further comprising:

providing a method for one of said possible requesting entities to register a change definition corresponding to said entity.

19. The method of claim 13, where said step of providing data change data regarding said data change to one of said requesting entities is performed only after it is determined that said one of said requesting entities has access privileges to said data change data.