How to create a DSN connection to SQL Server on link tables in Access 2003 and Access 2002 application tips

Source: Internet
Author: User
Tags dsn goto odbc access database
Method 1: Use the CreateTableDef method
The CreateTableDef method creates a linked table. To use this method, create a new module, and then add the following AttachDSNLessTable function to the new module.
Copy the code The code is as follows:

'// Name: AttachDSNLessTable
'// Purpose: Create a linked table to SQL Server without using a DSN
'// Parameters
'// stLocalTableName: Name of the table that you are creating in the current database
'// stRemoteTableName: Name of the table that you are linking to on the SQL Server database
'// stServer: Name of the SQL Server that you are linking to
'// stDatabase: Name of the SQL Server database that you are linking to
'// stUsername: Name of the SQL Server user who can connect to SQL Server, leave blank to use a Trusted Connection
'// stPassword: SQL Server user password
Function AttachDSNLessTable (stLocalTableName As String, stRemoteTableName As String, stServer As String, stDatabase As String, Optional stUsername As String, Optional stPassword As String)
    On Error GoTo AttachDSNLessTable_Err
    Dim td As TableDef
    Dim stConnect As String

    For Each td In CurrentDb.TableDefs
        If td.Name = stLocalTableName Then
            CurrentDb.TableDefs.Delete stLocalTableName
        End If
    Next

    If Len (stUsername) = 0 Then
        '// Use trusted authentication if stUsername is not supplied.
        stConnect = "ODBC; DRIVER = SQL Server; SERVER =" & stServer & "; DATABASE =" & stDatabase & "; Trusted_Connection = Yes"
    Else
        '// WARNING: This will save the username and the password with the linked table information.
        stConnect = "ODBC; DRIVER = SQL Server; SERVER =" & stServer & "; DATABASE =" & stDatabase & "; UID =" & stUsername & "; PWD =" & stPassword
    End If
    Set td = CurrentDb.CreateTableDef (stLocalTableName, dbAttachSavePWD, stRemoteTableName, stConnect)
    CurrentDb.TableDefs.Append td
    AttachDSNLessTable = True
    Exit Function

AttachDSNLessTable_Err:

    AttachDSNLessTable = False
    MsgBox "AttachDSNLessTable encountered an unexpected error:" & Err.Description

End Function


To call the AttachDSNLessTable function, call the code, which is similar to one of the following code examples in the Autoexec macro or in the Form_Open event of the startup form:
• When you use Autoexec, call the AttachDSNLessTable function, and then pass the parameters as shown below from the RunCode operation.
  AttachDSNLessTable ("authors", "authors", "(local)", "pubs", "", "")
• When you use the startup form, the code will be similar to the following with the Form_Open event.
Private Sub Form_Open (Cancel As Integer)
  If AttachDSNLessTable ("authors", "authors", "(local)", "pubs", "", "") Then
    '// All is okay.
  Else
    '// Not okay.
  End If
End Sub
When adding multiple linked tables to an Access database, you must adjust the programming logic.
 
Method 2: Use the DAO.RegisterDatabase method
The DAO.RegisterDatabase method creates a DSN connection in the Autoexec macro or in the startup form. Although this method does not delete the connection to the DSN, it does not help you solve the problem by creating the DSN connection in code. To use this method, create a new module, and then add the following CreateDSNConnection function to the new module.
'// Name: CreateDSNConnection
'// Purpose: Create a DSN to link tables to SQL Server
'// Parameters
'// stServer: Name of SQL Server that you are linking to
'// stDatabase: Name of the SQL Server database that you are linking to
'// stUsername: Name of the SQL Server user who can connect to SQL Server, leave blank to use a Trusted Connection
'// stPassword: SQL Server user password
Function CreateDSNConnection (stServer As String, stDatabase As String, Optional stUsername As String, Optional stPassword As String) As Boolean
  On Error GoTo CreateDSNConnection_Err

  Dim stConnect As String
  
  If Len (stUsername) = 0 Then
    '// Use trusted authentication if stUsername is not supplied.
    stConnect = "Description = myDSN" & vbCr & "SERVER =" & stServer & vbCr & "DATABASE =" & stDatabase & vbCr & "Trusted_Connection = Yes"
  Else
    stConnect = "Description = myDSN" & vbCr & "SERVER =" & stServer & vbCr & "DATABASE =" & stDatabase & vbCr
  End If
  
  DBEngine.RegisterDatabase "myDSN", "SQL Server", True, stConnect
    
  '// Add error checking.
  CreateDSNConnection = True
  Exit Function
CreateDSNConnection_Err:
  
  CreateDSNConnection = False
  MsgBox "CreateDSNConnection encountered an unexpected error:" & Err.Description
  
End Function
Note If you call the RegisterDatabase method again, the DSN is updated.

To call the CreateDSNConnection function, please code it similar to one of the following code examples in the Autoexec macro or in the Form_Open event of the startup form:
• When you use Autoexec, call the CreateDSNConnection function, and then pass the parameters, as shown below, from the RunCode operation.
  CreateDSNConnection ("(local)", "pubs", "", "")
• When you use the startup form, the code will be similar to the following with the Form_Open event.
Private Sub Form_Open (Cancel As Integer)
  If CreateDSNConnection ("(local)", "pubs", "", "") Then
    '// All is okay.
  Else
    '// Not okay.
  End If
End Sub
Note This method assumes that by using "myDSN" as the DSN name, you have created a linked SQLServer table in the Access database.

For more information about the CreateTableDef method, visit the following Microsoft Developer Network (MSDN) Web site:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/office97/html/output/F1/D2/S5A289.asp (http://msdn.microsoft.com/library /default.asp?url=/library/en-us/office97/html/output/F1/D2/S5A289.asp)
For the RegisterDatabase method, please visit the following MSDN Web site:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/office97/html/output/F1/D2/S5A2EA.asp (http://msdn.microsoft.com/library /default.asp?url=/library/en-us/office97/html/output/F1/D2/S5A2EA.asp)
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