Visual Basic

Re: Can i develope Client Server Application with access

11-Apr-05 20:25

Christian Graus wrote:
Welcome to the world of 'Access is crap'. If later versions allow multiple user access, certainly most of them do not. SQL Server is a real database, Access is not.

This comment is what is a load of crap. "Certainly most of them do not?"

The only certainty in this post is you certainly don't know what you are talking about.

Access has supported multiple user access since at least version 2.0. (Maybe in 1.0, I never used it).

Certainly Access is not appropriate for dozens of users and tables with millions of rows.

But there is nothing wrong with using Access as long as the number of users is a handful and the data tables are relatively small. Access has no problems when working in terms of scale of 3-5 users and tens of thousands of rows.

And for small applications not only is SQL Server overkill, it is a poor choice for other reasons.

Case in point: Small operations can back up their Access data by a simple file copy. Any developer who really believes that a smaller operation without on staff IT support can actually reliably backup and if need be restore their SQL Server data should not be developing software.

The original poster does not supply enough information to determine what the issue is.

However, speaking in general terms multiple users can work with Access data concurrently using all the major releases of ADO including 2.1 through .NET. You just need to specify the type of locking you want. Optimistic, BatchOptimistic are the most commonly used.

Robert

Christian Graus11-Apr-05 23:33

Christian Graus

11-Apr-05 23:33

You may ibe right, it could be stored procedures that most versions of Access does not support. All I know for sure is that Access is crap. I felt sure that others had said before that multi users was an issue.

rwestgraham wrote:
Small operations can back up their Access data by a simple file copy.

And so anyone with floppy can walk out with your data.

I use SQL Server even when I'll be the only user. Any DB system that doesn't support stored procs is just a nightmare.

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

Re: Can i develope Client Server Application with access

Dave Kreskowiak12-Apr-05 4:19

Re: Can i develope Client Server Application with access

12-Apr-05 4:19

Actually, Christian is right. Access is crap for any multiuser system.

Since its completely file based, it must be accessed using the underlying file system. This results in FAR more network traffic than using SQL Server, and is MUCH slower at doing the same job.

Since it's file system bound, a user from any machine that can see the database can grab a copy of it just by dragging and dropping it. Security is a joke.

You said all you have to do to backup it up is use a file copy? True, BUT!, in order to do so, everyone must disconnect from the database. Trust me, it happens every single day where I work.

Sure, SQL Server is overkill, but there's always MSDE and SQL Server Express to handle the smaller jobs, and they're FAR easier to upgrade to a full SQL Server than Access ever will be.

rwestgraham wrote:
Case in point: Small operations can back up their Access data by a simple file copy. Any developer who really believes that a smaller operation without on staff IT support can actually reliably backup and if need be restore their SQL Server data should not be developing software.

What case? I did it with a couple of small operations. If the backup operation is setup correctly, automated correctly, and stored in an appropriate site, it's not a problem. I could even fix any problem remotely, if needed.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

rwestgraham12-Apr-05 8:31

Re: Can i develope Client Server Application with access

12-Apr-05 8:31

Dave Kreskowiak wrote:
Actually, Christian is right. Access is crap for any multiuser system.

Since its completely file based, it must be accessed using the underlying file system. This results in FAR more network traffic than using SQL Server, and is MUCH slower at doing the same job.

When used properly - i.e a small system, both speed and network traffic are rarely issues with Access.

Security is not a major problem with Access if you set up work groups security. Even if a person copies the database they cannot access it outside of the workgroup.

If you are so anti-Access, what are you doing using it where you work. Surely you can sway everyone's opinion against Access since it is after all, "such a piece of crap"?

Dave Kreskowiak wrote:
What case? I did it with a couple of small operations. If the backup operation is setup correctly, automated correctly, and stored in an appropriate site, it's not a problem. I could even fix any problem remotely, if needed.

Backing up and restoring a single database is not particularly difficult. A full SQL Server restore? Different story. I would not want to have to try to walk a non-IT person through the process of a rebuilding an entire SQL Server. Good thing you can fix any problem remotely.

Many businesses successfully rely on Access every day.

I think some of you guys allow your personal prejudices about what's "good" and what's "crap" to allow you to make poor architectural decisions.

For every person out there who says Access is a piece of sh*t and SQL Server is a "real database" there is another person who will tell you that SQL Server is piece of sh*t and Oracle is a "real database". And it's true that SQL Servers choke on tasks that Oracle burns through in no time.

But so what? It's not about "faster" or "better". It's about picking tools and platforms that are appropriate for the end use.

I never give a client something that is much more complicated than they need or is less suitable for their operation's ability to support just because I think it is "better".

Robert

Dave Kreskowiak12-Apr-05 9:08

Re: Can i develope Client Server Application with access

12-Apr-05 9:08

rwestgraham wrote:
When used properly - i.e a small system, both speed and network traffic are rarely issues with Access.

Security is not a major problem with Access if you set up work groups security. Even if a person copies the database they cannot access it outside of the workgroup.

Not to mention workgroups in Access are a pain in the ass to use and administer. BTW: On my wire around here, the more I can reduce the chatter, the better. And yes, I've been in client sites where that was a concern. Now, it's a mandatory consideration in all the development I do.

rwestgraham wrote:
If you are so anti-Access, what are you doing using it where you work.

I didn't say I was using it. I haven't used it in MY development work in years, and refuse to go back. I find the control and supportability of MSDE/SQL Server much easier to deal with, but more importantly, much less likely to screw up in the first place.

rwestgraham wrote:
Surely you can sway everyone's opinion against Access

I didn't develop the system. I just have to keep it running somehow. And, no, I can't sway the opinion to get off Access. Believe me, with all the problems this thing has, I'd love to be able to rip it out and replace it with an SQL Server solution.

rwestgraham wrote:
Backing up and restoring a single database is not particularly difficult. A full SQL Server restore? Different story.

Same goes for a machine hosting an Access database, so I fail to see your point here. Since a total machine failure would have me out there rebuilding it either way...

rwestgraham wrote:
I think some of you guys allow your personal prejudices about what's "good" and what's "crap" to allow you to make poor architectural decisions.

Actually, it's not out "personal prejudices", but our "personal experiences" that dictate our architectural decision. Reliability, Supportability, and Scalability are the biggest factors I have to deal with in my work.

rwestgraham wrote:
It's about picking tools and platforms that are appropriate for the end use.

Reliability, Supportability, and Scalability...

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

rwestgraham12-Apr-05 9:57

Re: Can i develope Client Server Application with access

12-Apr-05 9:57

Dave Kreskowiak wrote:
Not to mention workgroups in Access are a pain in the ass to use and administer. BTW: On my wire around here, the more I can reduce the chatter, the better. And yes, I've been in client sites where that was a concern. Now, it's a mandatory consideration in all the development I do.

Workgroups are pretty easy to administer. People can do them in house easily. Much less difficult than setting up a SQL Server.

And if network traffic is an issue at a client site, then Access is probably not the correct choice anyway. You seem intent on ignoring the fact that I stress Access is only appropriate for small systems.

Dave Kreskowiak wrote:
Same goes for a machine hosting an Access database, so I fail to see your point here. Since a total machine failure would have me out there rebuilding it either way...

Absolutely not true. The person simply reinstalls Windows, reinstalls the application, pulls out the optical disk or whatever they copy their backups to, and copies the last Access backup to the working directory. If they have security they recreate the workgroups. The system is fully restored.

But I do agree about one thing. With MSDE or SQL Server yes, you are probably out there rebuilding it yourself. That's a luxury not everyone has. I am in Atlanta GA. Most of my clients are in Austin TX. If I had to fly out there to reinstall an application for a user group of 5 people because their hard drive crashed, somebody would be pissed, and rightfully so.

Dave Kreskowiak wrote:
Reliability, Supportability, and Scalability are the biggest factors I have to deal with in my work.

Key word YOUR work.

As far as reliability, I've had no real problems with Access. As far as supportability, as I've pointed out in length, my small application users can support themselves with Access. If I were to substitute MSDE this would no longer be the case.

My large application users have the either the resources in house to support a SQL Server or can afford the resources to have me support it for them.

Scalability is NOT a criteria in all systems. I recently did a pay-for-performance system for a client. It accesses their main database (A proprietary one that comes with their operations management system) and calculates some numbers and puts them into an Access database because that is a convenient way to spit out a report. The Operations manager can run it for the entire staff. An individual can run only their own data. It's not an application where scalability ever matters because the tasks run quickly, very little data is actually stored in Access, and there will never be more than a few people at most running reports at any given time.

This is exactly the sort of scenario where use of Access is appropriate.

What advantages would added by doing such an application with MSDE? None. The disadvantages? Well for starters I would have to create a more complicated build to install the MSDE service, plus create a build for the MSDE database itself, plus I would have additional support issues that my client would find unacceptable for such a simple application. MSDE is simply not appropriate for this particular application.

The key word is NOT always scalability. If scalability is a major criteria Access is not appropriate. The key word is always appropriate.

What part of the term appropriate do you not understand? You just don't get it do you?

Dave Kreskowiak12-Apr-05 12:24

Re: Can i develope Client Server Application with access

12-Apr-05 12:24

Great. Since our experiences are so different, we agree to disagree...

For you, Access is an option. For me, I don't find it appropriate for any multi-user system.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

rwestgraham12-Apr-05 14:15

Re: Can i develope Client Server Application with access

12-Apr-05 14:15

Dave Kreskowiak wrote:
For you, Access is an option. For me, I don't find it appropriate for any multi-user system.

But I knew that all along. Laugh | :laugh:

It's futile to argue with a fencepost about the hole that it's in.

I engage in these discussions only for the benefit of people who are open to evaluation of arguments that are more technically compelling than "it is a piece of sh*t" . Smile | :)

Robert

Abhaypppppppppp12-Apr-05 2:10

Abhaypppppppppp

12-Apr-05 2:10

Yes we can develop Client server application in VB by using Access
rs.CursorLocation = adUseClient
rs.Open sBuildQuery, cnn, adOpenKeyset, adLockOptimistic
use above string
i think u understand..

Abhay

Re: Can i develope Client Server Application with access

vertig073012-Apr-05 4:10

vertig0730

12-Apr-05 4:10

payal sheth wrote:
Its giving me Error like "Database is Exclusively locked by other User."

Someone has the DB open directly through access and that locks it to one person. I personally am running a .net program with 15 users with access to the DB with out a problem. The only trick i had to set up was to refresh the DB to the user once and a while. but no problems for me.

James Kennelly

Problems Displaying Forms

Chris Quick11-Apr-05 18:10

Chris Quick

11-Apr-05 18:10

I am creating an application that will create a notify window similar to outlook 2003 notify popup. I am making an asyncronous remoting call using system.thread that raises an event to show the form. However, the form shows up as a black box and then immediately disappears when the event is called. If I call the function through a menu item or button, it works fine. Here's the popup code:

Private Sub ATU_RetrieveDone(ByVal e As AsyncUpdater.AsyncUpdaterEventArgs) Handles ATU.RetrieveDone
    Me.UpdateTimer.Enabled = False
    If e.Forums Is Nothing Then
        UpdateTopicListView(e.Results) ' Updates a list view and
                                       ' displays the popup.
    Else
        UpdateForumListView(e.Forums)
    End If
    Me.UpdateTimer.Enabled = True
End Sub

Private Sub UpdateTopicListView(ByVal Topics As ResultsCollection)
    For index As Integer = 0 To Topics.Count - 1
        ...
    Next
    Dim Message As String
    Message = "{0} new topic updates have been retrieved from {1}"
    Me.ShowPopup(String.Format(Message, Topics.Count, ClientSettings.WebURL))
End Sub


Private Sub ShowPopup(ByVal Message As String, Optional ByVal TimeOut As Integer = 0)
    Dim displaytime As Integer
    If TimeOut < 1000 Then
        displaytime = ClientSettings.PopupTime * 1000
    Else
        displaytime = TimeOut
    End If
    Dim PW As New PopupWindow
    PW.SetProperties(NewMessagePopup.Blend, Message, displaytime)
    PW.ShowPopup()
End Sub

And here's routine that creates the popup using a seperate windows form.

Public Sub ShowPopup()
    Dim tbl As TaskBarLocation
    Dim workingArea As Rectangle
    Dim pt As Point

    pt = New Point
    pt.X = 0 : pt.Y = 0

    workingArea = SystemInformation.WorkingArea
    tbl = GetTaskBarLocation() ' Gets an enumerator
                               ' indicating the windows task bar
                               ' location.

    Select Case tbl
        Case TaskBarLocation.Bottom
            pt.X = workingArea.Right - Me.Width
            pt.Y = workingArea.Bottom - Me.Height
        Case TaskBarLocation.Left
            pt.X = workingArea.Left
            pt.Y = workingArea.Bottom - Me.Height
        Case TaskBarLocation.Right
            pt.X = workingArea.Right - Me.Width
            pt.Y = workingArea.Bottom - Me.Height
        Case TaskBarLocation.Top
            pt.X = workingArea.Right - Me.Width
            pt.Y = workingArea.Top
    End Select

    Me.Visible = False
    Me.Show()
    Me.Top = pt.Y
    Me.Left = pt.X
    Me.Visible = True
    tmrStartFade.Enabled = True ' Wait until elapsed to begin form fadeout
End Sub

Any ideas why this might be occuring?

Thanks!

Re: Problems Displaying Forms

Chris Quick12-Apr-05 3:35

Chris Quick

12-Apr-05 3:35

I've done some more research and it appears the problem is caused using timers. I've used both System.Timers.Timer and System.Windows.Forms.Timer and both give the same result, a black box that appears and then disappears. If I call the ShowPopup subroutine by clicking a button, it displays correctly. If the timer causes the form to be displayed, I get the black box.

Here's the logic steps used:
1) Timer.Tick event occurs
2) Tick Handler creates a new AsyncUpdater and invokes the GetUpdate method
3) GetUpdate creates a new thread and begins the remoting call
4) Once GetUpdate has completed the remoting call, the event RetrieveDone is raised.
5) The main form handles the event causing a list view to update it's list of items.
6) The ShowPopup method is called to display the popup.

Any help or ideas would be greatly appreciated. I can't understand why the manual invoking (pressing a button) works but the event handler doesn't.

Thanks!

vb6 - SQL via IP

mike2k511-Apr-05 16:03

mike2k5

11-Apr-05 16:03

Greetings

How can I use vb6 to connect using ip to a SQL database?

Thanks,

---- Mike

Dave Kreskowiak12-Apr-05 4:05

12-Apr-05 4:05

It's no different than any other connection to an SQL server. All you need to do is supply either the full DNS name to the server or the servers IP address:

Dim DBcon As New ADODB.Connection
Dim objCmd As New ADODB.Command
Dim objparameter As New ADODB.Parameter
Dim objRs As New ADODB.Recordset
    
    DBcon.ConnectionString = "Provider=sqloledb;" & _
        "server=[ServerName or IP Here];uid=UserId;pwd=Password;database=MyDatabase
    DBcon.CursorLocation = adUseClient
    DBcon.Open
    
    objparameter.Direction = adParamInput
    objparameter.Type = adVarChar
    objparameter.Size = 5
    objparameter.Value = "hello"
    objCmd.Parameters.Append objparameter
    
    objCmd.ActiveConnection = DBcon
    objCmd.CommandType = adCmdStoredProc
    objCmd.CommandText = "s_mysp"
    Set objRs = objCmd.Execute                       ' objCmd.Execute for no resultset
   
    set objRs.ActiveConnection = Nothing
    Set objCmd = Nothing
    DBcon.Close

Code snippet lifted from Nigel Rivett[^], without permission, of course.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mike2k512-Apr-05 5:59

mike2k5

12-Apr-05 5:59

Hi Dave,

Thanks for your post.
In VB6 I put the code in the form load sub.
I get the error "Compile error: User-defined type not defined" when I run thr project.
Am I missing a 'reference' or what?

Thanks again....

--- Mike

Private Sub Form_Load()
Dim DBcon As New ADODB.Connection
Dim objCmd As New ADODB.Command
Dim objparameter As New ADODB.Parameter
Dim objRs As New ADODB.Recordset

DBcon.ConnectionString = "Provider=sqloledb;" & _
"server=[ServerName or IP Here];uid=UserId;pwd=Password;database=MyDatabase"
DBcon.CursorLocation = adUseClient
DBcon.Open
End Sub

mike2k512-Apr-05 6:33

mike2k5

12-Apr-05 6:33

Problem solved.
I answered my own question.

I put the control Adodc1 on a form & the code connected to the database.

Thanks again for the help.

--- Mike

Dave Kreskowiak12-Apr-05 6:48

Reading a parallel port - Status Register

12-Apr-05 6:48

Oops! I forgot to mention that little tidbit. The code should work if you add a reference to the "Microsoft ActiveX Data Object Library" or something very similar. I can't remember the name off the top of my head.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

add_23_200511-Apr-05 12:59

add_23_2005

11-Apr-05 12:59

Hi,
I am trying to write a program to control a Digital Poteniometer via parallel. I was doing fine until I tried to work out how to read back some data from the device. I send a command to the chip, which then returns a serial stream of data out of a pin, which I have connected to S3 (status register) on the parallel port. I have been able to read the status register and then isolate S3 from this, but S3 is meant to be changing, so how can I make my program look for an event change in this register, ideally every x seconds or something?? Confused | :confused:

Any help would be greatly appreciated.

Regards,

Adam.

vertig073011-Apr-05 13:10

vertig0730

11-Apr-05 13:10

have you tried a timer. I use it to make clocks on my apps by telling it to read the system time every second.

James Kennelly

Anonymous11-Apr-05 16:47

Anonymous

11-Apr-05 16:47

This is what I use for a precision timer:

http://support.microsoft.com/default.aspx?scid=http://support.microsoft.com:80/support/kb/articles/Q172/3/38.asp&NoWebContent=1

How To Use QueryPerformanceCounter to Time Code

Anonymous11-Apr-05 16:50

Anonymous

11-Apr-05 16:50

Sorry, Here is the one for vb.net:

http://support.microsoft.com/default.aspx?scid=kb;en-us;306978

How To Use QueryPerformanceCounter to Time Code in Visual Basic .NET