Error when opening ADODB recordset using odbc dsn in MS Access - sql-server

Question

I have a MS Access application that has been in use for at least 10 years. Recently I moved my work to a new development machine with Office 365 and SQL Server Express 2019 installed. The machine OS is Windows 10 Pro. In my old machine my application would run just fine. There is a query using a stored procedure that retrieves a piece of data from a table in the SQL Server backend. I call this procedure using a ADODB recordset based on the stored procedure output. All my calls use a connection string based on an ODBC DNS. This connection string works fine on the new machine when relinking tables to the SQL Server backend, but when I use it in the ADODB connection I get an error "[Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified". On the old Windows 7 development machine this ran fine. It also runs on the client's machines which are Windows 10 and Office 365. The code that raises the error follows. The error occurs at the open connection line. The connection string is: ODBC;DSN=VROM;Trusted_Connection=Yes;APP=2019 Microsoft Office system;DATABASE=VROM1.
Set con = New ADODB.Connection
con.ConnectionString = DLookup("Link", "tblLinkData", "Use = True")
con.Open
Set rs = New ADODB.Recordset
My question "Is there a setting in SQL Server that could be causing this error?". As far as I can tell both systems are set up the same, but there is obviously something different between the two. Is there another reason this could be working on one system and not another?

Answer 1

Hum, where to start?
Ok, first up, if you using the ODBC panel to create a ODBC connection, then you NEVER were actually using a ADO connection in that DSN config = ODBC!!!!
That means you been feeing ADO a ODBC connection string. you can do this, but at least lets be aware of what is going on.
Next up:
Are you running the SQL browser service? You MUST do that now!. Don't know if you installed a later version of SQL SERVER, but a few versions ago you will find now that you MUST run the browser service.
This one:
The reason of course is that you can (may) have multiple instances of sql server running, and the default instance (SQLEXPRESS) now MUST BE specified. As noted older instances did NOT have this requirement. And to "resolve" the multiple instances, you now must run the SQL browser service. As noted, this was NOT a requirement in the past - it is now. That browser service is what connects the IP/server name to the instance, and you now in most cases have to run this.
There are exceptions, but you don't want much pain.
Next up:
For a VERY long time, it is recommended for Access linked tables you use a DSN-less connection. that way then at deployment time to all workstations, you don't need to setup a DSN on each workstation.
And if you link Access tables using a FILE dsn (not system or user), then upon the table link process, access BY DEFAULT converts all table links to DSN-less. That means once you linked, then you could even delete the DSN - you do NOT need it anymore.
Again: this ONLY holds true if and when you create a FILE dsn, and use that to link the tables. So, that takes care of the DSN-less linked tables.
Note that if you were to modify the DSN, you would have to link, since I just told you by default access creates + uses dsn-less links (assuming you used a FILE dsn to link).
now, you CAN of course use that SAME dsn for ADO, but that means you are feeding ADO a ODBC driver connection!!!
If you want to create a real ADO connection, then you would/could/should say use this:
Dim strCon As String
strCon = "Provider=SQLOLEDB;;Initial Catalog=TEST4; " & _
"Data Source =.\SQLEXPRESS;Trusted_Connection=yes"
Dim conn As New ADODB.Connection
conn.ConnectionString = strCon
conn.Open
Dim rst As New ADODB.Recordset
rst.Open "SELECT * from tblHotels", conn
Do While rst.EOF = False
Debug.Print rst!HotelName
rst.MoveNext
Loop
Now now how I used a "." for localhost. That could be replaced with (local), or in fact the computer (server) name say like this:
strCon = "Provider=SQLOLEDB;;Initial Catalog=TEST4; " & _
"Data Source =ALBERTKALLAL-PC\SQLEXPRESS;Trusted_Connection=yes"
Next up, make sure you enabled the TC/IP connections.
here:
However, since your case all along you actually been using ODBC driver with ADO, then I would not rock the boat.
But, check your settings as per above.
Since linked tables, and quite much everything else is DAO + odbc?
then I would probably not introduce ADO into that application for JUST calling + using sql server store procedures.
I as a general rule would say use this;
with currentdb.tabledefs("qryPT")
.sql = "exec MyProcName"
.execute
end with
Or, if it is to return data, then I would use this:
dim rst as DAO.RecordSet
with currentdb.tabledefs("qryPT")
.sql = "exec MyProcName"
set rst = .OpenRecordSet()
end with
So, I am hard pressed to find a reason to use ADO. Now of course since you been using ADO, then I guess I would continue to do so.
but, check the browser settings. And if the tables were linked using a FILE dsn, then they are dsn-less.
You could try feeding the ADO connection a existing connection from a existing linked table.
eg:
strCon = CurrentDb.TableDefs("dbo_tblHotels").Connect
strCon = Mid(strCon, 6)
Dim conn As New ADODB.Connection
conn.ConnectionString = strCon
conn.Open
Skipping the first 6 chars skips this part:
ODBC;DRIVER=SQL Server;SERVER=ALBERTKALLAL-PC\SQLEXPRESS;
UID=AlbertKallal;Trusted_Connection=Yes;APP=Microsoft Office 2010;
DATABASE=Test4;Network=DBMSLPCNM
So once again we are feeding ADO ODBC connection string.
(of course above connection string is one line).