Status: Solved
Priority: Medium
Security: Public
Views: 109
Last Modified: 2016-07-31

Determine whether I have a valid connection to a SQL database

I have the following code which attempts to create a query and recordset to determine whether the parameters in a form for ServerName and dbName are valid:

strDriver = "SQL Server Native Client 11.0"
cnn = "ODBC;DRIVER=" & strDriver & ";SERVER=" & ServerName _
    & ";Trusted_Connection=Yes;APP=Microsoft Office 2003;WSID=" & ServerName _
    & ";DATABASE=" & DBName & "; "
Set db = CurrentDb
Set qdf = db.CreateQueryDef("")
qdf.Connect = cnn
qdf.ReturnsRecords = True
qdf.SQL = "SELECT top 1 dbo.SomeTableName. * from dbo.SomeTableName"
Set rs = qdf.OpenRecordset()
rs.Close

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This code bombs out on the line that starts: SET rs =

With an error that reads:

3151 ODBC--connection to 'SQL Server Native Client 11.0ServerName' failed.

But if I copy the connection string generated above:

ODBC;DRIVER=SQL Server Native Client 11.0;SERVER=ServerName;Trusted_Connection=Yes;APP=Microsoft Office 2003;WSID=ServerName;DATABASE=dbName;

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and create a new pass-through query with identical SQL string, it returns the 1 record I'm looking for, so the connection is valid, but I keep getting this error message.

Any ideas what I might be doing wrong?

Dale Fye

Asked: 2016-07-26

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2 Solutions

LVL 86

Scott McDaniel (Microsoft Access MVP - EE MVE )Infotrakker SoftwareCommented: 2016-07-26

What's the reasoning for creating a QueryDef and then opening the Recordset? In other words - why not just open the Recordset directly:

strDriver = "SQL Server Native Client 11.0"
cnn = "ODBC;DRIVER=" & strDriver & ";SERVER=" & ServerName _
& ";Trusted_Connection=Yes;APP=Microsoft Office 2003;WSID=" & ServerName _
& ";DATABASE=" & DBName & "; "
Dim rs As New ADODB.Recordset
rs.Open "Your SQL", cnn

LVL 50

Dale FyeAuthor Commented: 2016-07-26

Scott,

Guess I'm just used to working with DAO, and rarely use ADO. I'll give that a try.

Dale

LVL 50

Dale FyeAuthor Commented: 2016-07-26

Scott,

I'm getting an error:

-2147467259 [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified

But with the exact same SQL string with is assigned to the linked tables

LVL 86

Scott McDaniel (Microsoft Access MVP - EE MVE )Infotrakker SoftwareCommented: 2016-07-26

Try a different connection string:

Provider=SQLNCLI11;Server=myServerAddress;Database=myDataBase;Uid=myUsername;
Pwd=myPassword;

REfer to here for more info on strings:

https://www.connectionstrings.com/sql-server/

LVL 71

Éric MoreauSenior .Net ConsultantCommented: 2016-07-26

what do you have in your ServerName and DBName variable? what if you do Msgbox(cnn)? Do you see a valid connection string?

LVL 5

bfuchsCommented: 2016-07-26

I tried your code with DSN like following and worked. (A2003)

ODBC;DSN=MyDbName;UID=MyUserName;PWD=MyPwd;DATABASE=MyDbName

LVL 31

Olaf DoschkeSoftware DeveloperCommented: 2016-07-27

qdf is created in CurrentDb, and then you set a connstring? To the same database? Another? Forget this, if it is normal, I don't work much with Access, but it seems odd to root a querydefinition in some database and then impose a new connection on it.

Bye, Olaf.

LVL 50

Dale FyeAuthor Commented: 2016-07-27

OK, so this is really strange. Assume:

ServerName = "XXX"
DBName = "YYY"

I found that if I construct my connection string dynamically at runtime (lines 1&2) below, I get an error message on the rs.Open line below. But if I define the connection string as depicted in lines 3&4, the recordset opens properly. Anybody have any ideas?

'   strConn = "DRIVER={SQL Server Native Client 11.0};" _
            & "SERVER=" & ServerName & ";DATABASE=" & DBName & ";Trusted_Connection=Yes;"
    strConn = "DRIVER={SQL Server Native Client 11.0};" _
            & "SERVER=XXX;DATABASE=YYY;Trusted_Connection=Yes;"

    Dim rs As New ADODB.Recordset
    rs.Open "SELECT COUNT(*) as RecCount FROM SomeTable", strConn

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Prior to running this segment of code, I get the ServerName and dbName from the registry, use the NZ() function to give them a default value and then TRIM() the values to make certain that the strings don't contain any extraneous characters.

When I print the connection strings, they are identical but the first returns the error:

-2147217843 [Microsoft][SQL Server Native Client 11.0][SQL Server]Cannot open database "YYY" requested by the login. The login failed.

LVL 50

Dale FyeAuthor Commented: 2016-07-27

I'm an idiot, or I need better glasses.

The dbName variable contained an underscore instead of a hyphen in one character and I kept missing it when I looked at the error message and the connection strings when printed, one above the other.

Thanks all, for you help and recommendations. I actually prefer the ADO method you show above Scott, over the querydef method I've used in the past.

Dale

LVL 71

Éric MoreauSenior .Net ConsultantCommented: 2016-07-27

so my comments in ID 41730391 were on the spot!

LVL 86

Scott McDaniel (Microsoft Access MVP - EE MVE )Infotrakker SoftwareCommented: 2016-07-28

I'm an idiot, or I need better glasses.

I always blame it on the glasses!!

Glad you got it sorted. I much prefer to use the ADO method when working with SQL Server (or any other server database, for that matter).