Browse Prior Art Database

Lock-Holding Transaction Control Model for Client/Server Applications

IP.com Disclosure Number: IPCOM000028377D
Original Publication Date: 2004-May-14
Included in the Prior Art Database: 2004-May-14
Document File: 3 page(s) / 44K

Publishing Venue

IBM

Abstract

Disclosed is a programing method for controlling a database transaction. In this method, a trasaction-control component requests an applicaion to put a right type of sql statement by sending an event at the right timing. Using the component, applicaition programmers need not care when to put sql statements, but only program to respond the events which the component send.

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Lock-Holding Transaction Control Model for Client /Server Applications

This invention is for the applicaions which needs the 3 requirements listed below:
(1) The data loaded on a screen must be the same as the data in their data source at the loaded timing .
(2) The data on a screen cannot be changed on the data source by other users .
(3) A change of the data on the screen must not be refused in reflecting the change to the data source . These 3 requirements are equivalent to the 2 rules, which are:
(a) Locks records when they are loaded on a screen.
(b) Keeps the lock while the records are on the screen.

In a traditional way, in order to realize the 2 rules mentioned above, each application has to contain a database transacition logic if an sql statement is different than other application. Fig.1 indicates that case. The three of applications contain the same transaction flow.

Application-A Application-B Application-C

START

OK

Update-A

N

Y

Y

Commit

Lock-A

N

OK

END

Rollback

Select-A

START

OK

Update-B

N

Y

Y

Commit

Lock-B

N

OK

END

Rollback

Select-B

START

OK

Update-C

N

Y

Y

Commit

Lock-C

N

OK

END

Rollback

Select-C

Fig. 1

In the invented method, transaction-control flows are independent of application programs. Fig. 2 indicates the new method case. Each application does not contain a transaction-control logic. Only the transaction-control component controls a transaction-control flow. When an application wants to update, insert, delete or lock a record, the application calls the start point of the transaction-control component. Then the component controls the sequence and sends events when sql statements are to be put.

1

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Application-A Application-B Application-C

Update-A

Lock-A

Select-A

Update-B

Lock-B

Select-B

Update-C

Lock-C

Select-C

Receives Events

Receives Events

Receives Events

Sends Request

Events

Sends Request

Events

Sends Request

Events

START

Request Update

OK

N

Y

Y

Commit

Request Lock

Request Select

END

N

OK

Rollback

Transaction-Control Component

Fig. 2

Fig. 3 indicates details of the transaction-control process of saving edited data. ①The application program calls the start point of the transaction-control component with the application ID as an argument.
②The component sends an event of "Request-Update" to unspecified applications. ③The application progr...