Sending application wide Alert

hi,

Just need little help with logic please.

If I have a application open on 20+ system, all of which could be opened at different times.

How would I be able to ensure an Alert went to all OPEN Application.

I have the code for making a pop up alert already

Also use Access database

I was thinking of using 2 timers

1st timer checks every 5 minus if Alert Table has any alerts marked as not read (boolean)
If finds any then it displays the alerts, and disables itself and starts Timer 2

Timer 2 is set for 4 mins, so after 4 mins it will set the read flag in the table with the alerts to Read (and then stop itself and restart Timer 1.

I'm not sure if all the system would get display the Alerts before they are disabled (due to different startup times).

Can someone please help with my Logic.

Thanks

Using VB 2010, Access

Twenty plus concurrent users on an Access DB on a network? I'm not sure that the alerts are the biggest issue.

However, if you have a database, I think a slightly different design would suit better. So, you have a table of alerts. Each alert should have a primary key, and a posted time (record when the alert was added to the table). Then, have a second table that held the ID for the installation (each installation could have their own GUID fairly easily), and the key for the alert. When an alert is shown on system X, write the alert key and X into the table. Then you only need one timer to periodically look at the table to see if there are any alerts for that system for which there is no record in the second table. That's a simple JOIN.

The purpose for adding a date for when the alert was added is not as clear. It just seems like person A might go on vacation for a month, and when they get back they might not want to see every alert that they missed during that month, so the date on the alert could act as something of an expiration date: Any alert older than X isn't worth showing, no matter what.

So, that's my suggestion. As to Access, it was never really intended to work with concurrent users, and makes some decisions on locking that are quite unfortunate. Furthermore, if a connection is open and the network connection drops, you are likely to see strange and unpredictable corruption in the database. You might consider something more robust for a multi-user environment, such as SQL Server Express, which is free.

Thanks for the info that's helpful.

The Access db started as read only access and had no need for users to write to it, I came up with the idea of alerts/notifications recently, and do have access to SQL server, so I might move it over to the server.