Compiler Error: User-defined types not defined

Question

I get the compile-time error "User-defined types not defined" on this line:

Dim cn As ADODB.Connection

What could be wrong?

Code:

Sub test()

    Dim cn As ADODB.Connection

    'Not the best way to get the name, just convenient for notes

    strFile = Workbooks(1).FullName
    strCon = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & strFile & ";Extended Properties=""Excel 8.0;HDR=Yes;IMEX=1"";"
    Set cn = CreateObject("ADODB.Connection")
    'For this to work, you must create a DSN and use the name in place of

    'DSNName

    'strSQL = "INSERT INTO [ODBC;DSN=DSNName;].NameOfMySQLTable " & "Select AnyField As NameOfMySQLField FROM [Sheet1$];"
     strSQL = "SELECT F1 FROM [Sheet1$];"
     cn.Execute strSQL
End Sub

Answer 1

I had forgotten to add a reference to "Microsoft ActiveX Data Objects 2.5 Library": This reference is required for early binding .

How to get to that reference:

Tools > References > Check the checkbox in front of "Microsoft ActiveX Data Objects 2.5 Library"

Other libraries that work include:

Microsoft ActiveX Data Objects 2.6 Library

Microsoft ActiveX Data Objects 2.7 Library

Microsoft ActiveX Data Objects 2.8 Library

Microsoft ActiveX Data Objects 6.1 Library

Answer 2

You can use late binding:

Dim cn As Object

will make the problem go away. VBA will make the reference automatically when the Set cn = CreateObject("ADODB.Connection") statement is executed.

Answer 3

I tried adding Microsoft ActiveX Data Objects 2.5 and 2.8 library, but it did not work out. But when I tried creating new object like below it worked.

Set cn = CreateObject("ADODB.Connection")