ADP are mainly based on ADO and not DAO; so there is not CurrentDB by
default.  However, if you insist, you can create a DAO.Database object and
connect it to your backend database.  Here are some information and pieces
of code (not from me) that have already been published in the past in the
m.p.access.adp.sqlserver newsgroup:

Public Function DAODatabase() As DAO.Database

  Dim cnn As ADODB.Connection
  Dim dbDAO As DAO.Database
  Dim strConnect As String

  Set cnn = CurrentProject.Connection

  ' Is the connection based on MSdataShape- or SQLOLEDB-provider?

  If InStr(cnn.Provider, "Microsoft.Access.OLEDB") > 0 Or
InStr(cnn.Provider, "MSDataShape") > 0 Or InStr(cnn.Provider, "SQLOLEDB") >
0 Then

      ' Build connection string
      strConnect = "ODBC;driver=SQL Server;server=" & cnn.Properties("Data
Source") & ";"
      ' Database Name
      strConnect = strConnect & "database=" & cnn.Properties("Initial
Catalog") & ";"
      ' SQL Server- or Windows-security?
      If cnn.Properties("Integrated Security") = "SSPI" Then
          strConnect = strConnect & "Trusted_Connection=Yes;"
      Else
          strConnect = strConnect & "UID=" & cnn.Properties("User ID") &
";"
          strConnect = strConnect & "PWD=" & cnn.Properties("Password") &
";"
      End If
  Else
      MsgBox "DAO-Database not opened!"
      Set DAODatabase = Nothing
      Exit Function
  End If

  ' Open Database
  Set dbDAO = DBEngine.OpenDatabase("", False, False, strConnect)
  Set DAODatabase = dbDAO

End Function

Sub DAO_Test()
  Dim db As DAO.Database
  Dim rec As DAO.Recordset

  Set db = DAODatabase()
  Set rec = db.OpenRecordset("select * from tblFilme", dbOpenForwardOnly)
  Do Until rec.EOF
      Debug.Print rec!Filmtitel
      rec.MoveNext
  Loop
  Set db = Nothing
End Sub

There is a blank space for "Data Source", "Initial Catalog" and "User ID".
For Update and other queries that modify the database, you also need to add
the parameter « dbSeeChanges » and for reasons that I don't remember, I also
add the parameter « dbFailOnError  » :

Set db = DAODatabase()

Dim sql as string
sql = "Update Joueurs Set Joueurs.NoChandail = ...."

db.Execute sql, dbFailOnError Or dbSeeChanges

You need to specify to ask for DAO objects in the VBA code:

   Dim db As DAO.Database
   Set db = DAODatabase()

   Dim rs As DAO.Recordset
   Set rs = db.OpenRecordset (sql_string, dbOpenDynaset, dbSeeChanges)

If you want to have transactions, you can also first open a Workspace. Also,
after taking a quick look at it, maybe it will be a good idea to explicitely
close the database before setting to Nothing.

Finally, using DAO inside an ADP project should only be considered as a
quick patch.