Check if db is open (1 Viewer)

[JohnPapa]

I would like to be able to check if a db is open and if it is to prevent the user from proceeding.

I use the Access 2013 Runtime. I can check if a db is open by trying to open Exclusively, using something like

https://support.microsoft.com/en-gb/kb/210359

But if the db is already open Not exclusively and I try to open it exclusively it does not raise an error and it allows the user to open the db in Read Only mode.

I would like to be able to prevent this, because careless and/or inexperienced users may open several instances of the db.

Of course, if the db is already open exclusively it does not allow you to open it exclusively another time.

Thanks

 

[spikepl]

I used the code below picked up somewhere to prevent more than one instance of my current db to open. It can probably be adopted to your needs.

Updtae: On reflection, is there no way to see how a particualr insatnce has been opened ? Id' look into that. Because the solution I gave you can be noticeably slow.

Function IsRunning() As Integer
    Dim DB As dao.Database


    If gcfHandleErrors Then On Error GoTo IsRunning_Error

    Set DB = CurrentDb

    If TestDDELink(DB.Name) Then

        '("PTD Shipping is already open")

        DB.Close

        Set DB = Nothing

        DoCmd.Quit

    End If


IsRunning_Exit:

    On Error Resume Next

    Exit Function

IsRunning_Error:

    Select Case Err.Number

        Case Else

            MsgBox "Error " & Err.Number & " (" & Err.Description & ") in procedure IsRunning of Module InitTools"

            Resume IsRunning_Exit

    End Select

End Function



Function TestDDELink(ByVal strAppName$) As Integer

    Dim varDDEChannel

    On Error Resume Next

    Application.SetOption ("Ignore DDE Requests"), True

    varDDEChannel = DDEInitiate("MSAccess", strAppName)

    ' When the app isn't already running this will error

    If Err Then

        TestDDELink = False

    Else

        TestDDELink = True

        DDETerminate varDDEChannel

        DDETerminateAll

    End If

    Application.SetOption ("Ignore DDE Requests"), False

End Function

 

[JohnPapa]

Thanks spikepl, will try it out.

A sort of relevant question, if I open exclusively the FE on pc1 can I open the same FE exclusively on pc2? Also can I change the BE db on pc3 from pc1 and pc2 when open exclusively?

Thanks

 

[spikepl]

It doesn't check for exclusive or not. It checks for instances either on same machine or under same login name - I suspect the former. So it is also not related to your question about BE.

 

[JohnPapa]

Unfortunately, the same login may appear on other pcs.

 

[vbaInet]

There's an API that stops multiple instances of an application from being instantiated but I can't remember what it's called.

However, if we think about this in simple terms, GetObject() will fail if the db is opened so you could give that a try. The other thing to do is to check for a lock file, but the only downside with this is that if the user's db crashes the lock file doesn't get deleted. For the third option, there's a schema in Access that lists users.

 

[ryetee]

There's an API that stops multiple instances of an application from being instantiated but I can't remember what it's called.

However, if we think about this in simple terms, GetObject() will fail if the db is opened so you could give that a try. The other thing to do is to check for a lock file, but the only downside with this is that if the user's db crashes the lock file doesn't get deleted. For the third option, there's a schema in Access that lists users.

is the API something like createmutex?

Oh and don't know if this works but there's code here..
http://access.mvps.org/access/api/api0041.htm