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Access ODBC to SQL Server 'Connection busy with results from another command'

Posted on 2011-09-26
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Last Modified: 2012-06-22
I have been working on an Access front-end to a SQL Server 2008 Express database. I have a main form with several sub-forms and after adding a further couple of sub-forms today, I find whenever I try to add a new record. This only happens with the new subforms, the existing ones being OK. The message is as follows..

ODBC Call failed.
[Microsoft][SQL Server Native Client 10.0]Connection is busy with results from another command (#0)


This seems to be a fairly common problem on the 'net although I've yet to find a solution. The subforms in question are very basic forms based on simple tables with no specific code involved so I cannot understand the issue. I think I read somewhere previously that adding a timestamp field can help although this hasn't in this case.

Any help appreciated.
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Question by:nigelr99
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Expert Comment

by:_-W-_
ID: 36601275
Instead DAO.Recordset use ADODB.Recordset? Also, try turning on MARS.

Using MARS from ODBC and OLE DB
To use MARS with ODBC the connection string addition is “MARS_Connection=yes”, or you can a connection attribute as follows:
    SQLSetConnectAttr(hdbc, SQL_COPT_SS_MARS_ENABLED,SQL_MARS_ENABLED_YES, SQL_IS_UINTEGER);
before calling SQLDriverConnect or SQLBrowseConnect. With OLE DB, the provider string addition for IDBInitialize::Initialize is “MarsConn=yes”, or “MARS Connection=true” if you use an initialization string with IDataInitialize::GetDataSource. You can also enable MARS programmatically as follows:

    IDBInitialize *pIDBInitialize = NULL;
    IDBProperties *pIDBProperties = NULL;
    // Create the data source object.
    hr = CoCreateInstance(CLSID_SQLNCLI, NULL, CLSCTX_INPROC_SERVER,IID_IDBInitialize, (void**)&pIDBInitialize);
    hr = pIDBInitialize->QueryInterface(IID_IDBProperties, (void**)&pIDBProperties);

    // Set the MARS property.
    DBPROP rgPropMARS;
    IDBProperties rgPropMARS.dwPropertyID = SSPROP_INIT_MARSCONNECTION;
    rgPropMARS.dwOptions = DBPROPOPTIONS_REQUIRED;
    rgPropMARS.dwStatus = DBPROPSTATUS_OK;
    rgPropMARS.colid = DB_NULLID;
    V_VT(&(rgPropMARS.vValue)) = VT_BOOL;
    V_BOOL(&(rgPropMARS.vValue)) = VARIANT_TRUE;

    // Create the structure containing the properties.
    DBPROPSET PropSet;
    PropSet.rgProperties = &rgPropMARS;
    PropSet.cProperties = 1;
    PropSet.guidPropertySet = DBPROPSET_SQLSERVERDBINIT;

    // Get an IDBProperties pointer and set the initialization properties.
    pIDBProperties->SetProperties(1, &PropSet);
    pIDBProperties->Release();
    // Initialize the data source object.
    hr = pIDBInitialize->Initialize();
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Accepted Solution

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nigelr99 earned 0 total points
ID: 36601768
Thanks for the response.. with it being somewhat intimidating as I'm using DSN for database connectivity and keeping things as simple as possible, I looked at this issue again. It turns out that by simply setting a check-box on the sub-form to a default value of 0 (thereby preventing a null value causing an error), the 'busy' error has gone!

Looks like the odbc error was a red herring when in fact the real problem was attempting to write a null value into a field where I've disallowed nulls?
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Expert Comment

by:Jeffrey Coachman
ID: 36642041
"The subforms in question are very basic forms based on simple tables with no specific code involved so I cannot understand the issue."

"I have a main form with several sub-forms and after adding a further couple of sub-forms today,"

So your main form possibly contains more that 4 subforms?

Can you explain the purpose of this main form that it needs possibly over 4 subforms?
Are the subform related "vertically" (multiple Nested subforms), or horizontally (one man form and many subforms at the same level below the main form)

Typically you will have a main form and possibly two subforms, but not more than that because it can become confusing for the user (and the developer)
My theory here is the complexity of the form(s) may be contributing to the error (as I have never gotten this error in my multiform basic setups)

"I think I read somewhere previously that adding a timestamp field can help "
Yes, and also make sure to have a primary key in each table.

Finally, Access contains a few settings that you can use to manage possible "Timing" issues like this.
(see attached screenshot)


JeffCoachman
untitled.JPG
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Author Comment

by:nigelr99
ID: 36709504
Well, bit of a long story, but the main form is not linked to any of the subforms.. it originally started life as a simple 'admin' form with a few subforms to view/edit some basic tables. I had a simple button interface to show / hide one subform at a time.
This has grown beyond it's original idea so I'll be looking to redesign, especially in light of odbc issues etc.
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Expert Comment

by:Jeffrey Coachman
ID: 36710296
OK

Then first create the simple main form and test.
Then add one form at a time until the issuse appears.

"but the main form is not linked to any of the subforms.. it originally started life as a simple 'admin' form with a few subforms to view/edit some basic tables."
Then simply create one form for each table and use a "Menu form" to open each one individually.
  "Keep it simple"

;-)

JeffCoachman
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Expert Comment

by:Jeffrey Coachman
ID: 36714513
If you build the individual forms, you can use the "switchboard manager" in access to create a "Menu" system.
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Author Closing Comment

by:nigelr99
ID: 37023075
Null field value seemed to be causing the error so I think we can close the question. Thanks for further help from everyone.
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