(1)
Dim db As DAO.Database
Dim rs As DAO.Recordset
Dim bolFound As Boolean
'open external db
Set db = OpenDatabase(CurrentProject.Path & "\ExternalDBname.accdb", False, False)
'open recordset based on what you like to find
Set rs = db.OpenRecordSet("Select * From ExternalTableName Where FieldInExternalTable = '" & yourSearchString & "'")
bolFound = (rs.BOF And rs.EOF)
'housekeeping
rs.Close
Set rs=Nothing
Set db=Nothing