Distributing database differences corresponding to database change events made to a database table located on a server computer

• US 5,999,947 A
• Filed: 05/27/1997
• Issued: 12/07/1999
• Est. Priority Date: 05/27/1997
• Status: Expired due to Term

• Current Assignee: Pure Data Systems, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Arkona LLC
• Inventors: Zollinger, John M., Devine, Johnathan
• Primary Examiner(s): Lintz, Paul R.
• Assistant Examiner(s): Colbert, Ella
• Application Number:
  US08/863,680
• Time in Patent Office: 924 Days
• Field of Search: 707/203, 707/1, 707/3, 707/201, 711/113, 711/5, 395/200.59
• US Class Current: 1/1
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A method, computer program product, and system that allows changes made to an original database table found on a server computer to be reflected in client copies of the database table based on intermittent client requests for synchronization. A server makes periodic updates of table differences between a current table receiving database change events and a reference table. Each client copy of a database table and update created by the server has a sequential version number associated therewith. The server will compare the version number of a client copy of a database table with the most recent version number of the table on the server to determine which updates need be applied in order to make the client copy current. Next, the updates will be translated from a generic format into instructions that are specific to the type of database engine being run on the client. Finally, the instructions are transmitted to the client (along with the new version number) so that the client may operate the database engine to apply the instructions for making the database table current with the original managed on the server.

Claims

1. A method of distributing database differences corresponding to change events made to a database table located on a server computer to client copies of the database table located on one or more client computers comprising the steps of:

creating and storing on the server computer one or more sequentially versioned updates, each update containing database differences in a generic format, the database differences corresponding to database change events made to the database table since the preceding update;

receiving, from a client computer, a request for all the database differences needed to make the client copy of the database table current;

determining which updates are necessary for making the client copy of the database table current;

ascertaining a client database engine type wherein the client copy of the database table is held;

generating and translating specific database differences, selected based on the necessary updates, into instructions based on the ascertained database engine type prior to transmission; and

transmitting the specific database differences to the client computer so that the client computer may execute the instructions on the client database engine, thereby making the client copy of the database table current in response to the specific database differences translated into the instructions.

2. A method as recited in claim 1 wherein the client database engine type is ascertained by the client computer supplying the client database engine type as part of the request.

3. A method as recited in claim 1 wherein the client database engine type is ascertained by reference to profile information regarding the client computer.

4. A method as recited in claim 1, further comprising the step of receiving from the client computer a plurality of requests for synchronization, wherein the plurality of requests for synchronization are received randomly in time.

5. A method as recited in claim 1 wherein the client is intermittently connected to the server computer.

6. A method of distributing database differences corresponding to database change events made to a database table located on a server computer to client copies of the database table located on one or more client computers, each client computer capable of having different database engines comprising the steps of:

storing database differences at the server computer in a generic format;

receiving from a client computer a request for all database differences needed to make a client copy of the database table current;

translating the differences from the generic format into instructions having a specific format compatible with the type of database engine associated with the client copy of the database table; and

transmitting the instructions to the client computer for execution on the client database engine to make the client copy of the database table current.

7. A method as recited in claim 6 wherein the type of database engine is ascertained by the client computer supplying the type of database engine as part of the request.

8. A method as recited in claim 6 wherein the type of database engine is ascertained by reference to profile information regarding the client computer.

9. A method as recited in claim 6 further comprising the steps of:

creating and storing on the server computer one or more sequentially versioned updates containing database differences corresponding to database change events made to the database table since the preceding update;

determining which updates are necessary for making the client copy of the database table current; and

generating the database differences based upon the necessary updates prior to the step of translating the differences into instructions.

10. A method as recited in claim 9 wherein the client computer supplies a client version of the client copy of the database table as part of the request and the step of determining which updates are necessary is done by comparing the client version with the latest update version.

11. A method as recited in claim 9 wherein a client version of the client copy of the database table is referenced from client profile information and the step of determining which updates are necessary is done by comparing the client version with a latest update version.

12. A computer-readable medium having computer-executable instructions for performing the steps recited in claim 6.

13. A method as recited in claim 6 wherein the client is intermittently connected to the server computer.

14. A computer program product comprising:

a computer usable medium having computer readable program code means embodied in said medium for distributing database differences corresponding to database change events made to a database table located on a server computer to client copies of the database table located on one or more client computers, each client computer capable of having one or more database engines, said computer readable program code means comprising;

means for creating and storing on the server computer one or more sequentially versioned updates, each update containing database differences that are stored in a generic format and correspond to database change events made to the database table since the preceding update;

means for receiving from a client computer a request for all the database differences needed to make the client copy of the database table current;

means for determining which updates are necessary for making the client copy of the database table current;

means for ascertaining the client database type associated with the client copy of the database table;

means for translating the specific differences based upon the necessary updates from the generic format into instructions having a specific format compatible with the client database type; and

means for transmitting the instructions to the client computer for execution on the client database engine to make the client copy of the database table current.