Question

I have a large Access VBA/SQL Server application. In each function there is the same ADODB connection.

How do I replace those with a single function that can be called each time, to save space.

Public Function ConnectionString() As ADODB.Connection
    Dim CN As ADODB.Connection
    
    Set CN = New ADODB.Connection
        
    With CN
        .Provider = "Microsoft.Access.OLEDB.10.0"
        .Properties("Data Provider").Value = "SQLOLEDB"
        .Properties("Data Source").Value = DLookup("Source", "tbl_Connection")
        .Properties("Initial Catalog").Value = DLookup("Catalog", "tbl_Connection")
        .Properties("Integrated Security").Value = SSPI
        .Open
    End With
        
    ConnectionString = CN
    
End Function

It seems like this should return that connection, but there is an error message:

User-Defined Function not found

on the line ConnectionString = CN.

Answer 1

You need to Set the return value:

Set ConnectionString = CN

---

Plus, if it’s always the same ADODB connection anyway, you can save it in a variable and “recycle” it from there, so the actual creation of the connection happens exactly once (when the ConnectionString function is called for the first time).

Private CN As ADODB.Connection 'variable in the module - NOT in the function

Public Function ConnectionString() As ADODB.Connection

If CN Is Nothing Then

    Set CN = New ADODB.Connection

    With CN
        'do stuff
    End With

End If

Set ConnectionString = CN

End Function