I think this is a logic question they haven't worked through. Let's say
company A and B are using the on-line server and company C is not. All
three start the day the same way with company A offering 500 shoes for
sale. Company B likes the shoes and buys 400 of them. The database on
the central server now says there are 100 shoes left. But Company C,
which also likes the shoes, thinks there are 500 since they haven't
updated their version of the database. They put in an order for 200
shoes and only find out later they have been shipped 100, with 100 back
ordered.
This is just a simple example with three companies. Multiply that by
hundreds of transactions and hundreds of companies and you get a real
nightmare.
The solution is pretty simple. The companies who don't want to be
connected all day only connect when they want to conduct a transaction.
The data is updated the moment they log on, they conduct their purchase
and then they log off.
Frank Hilliard
http://frankhilliard.com/
Ma Siva Kumar wrote:
>We are developing an application for leather industry using PostgreSQL with
>PHP scripting. The program will be run from a central server and buyers and
>sellers will login using internet connection and update/exchange information
>through the system.
>
>Some companies do not want to be connected to the internet throughout the
>day. They want to use the system from a local server during the day and
>update the data to the central server (and get the updated data from the
>server) once or twice a day.
>
>Can someone please advise me, how this can be accomplished? That is, to make
>the two databases hand shake and exchange the changes effected since they
>last met.
>
>Best regards,
>
>
>Siva,
>Chennai, Tamil Nadu
>
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