CCommand::Close
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The latest version of this topic can be found at CCommand::Close.
Releases the accessor rowset associated with the command.
Syntax
void Close( );
Remarks
A command uses a rowset, result set accessor, and (optionally) a parameter accessor (unlike tables, which do not support parameters and do not need a parameter accessor).
When you execute a command, you should call both Close and ReleaseCommand after the command.
When you want to execute the same command repeatedly, you should release each result set accessor by calling Close before calling Execute. At the end of the series, you should release the parameter accessor by calling ReleaseCommand. Another common scenario is calling a stored procedure that has output parameters. On many providers (such as the OLE DB provider for SQL Server) the output parameter values will not be accessible until you close the result set accessor. Call Close to close the returned rowset and result set accessor, but not the parameter accessor, thus allowing you to retrieve the output parameter values.
Example
The following example shows how you can call Close and ReleaseCommand when you execute the same command repeatedly.
void DoCCommandTest()
{
HRESULT hr;
hr = CoInitialize(NULL);
CCustomer rs; // Your CCommand-derived class
rs.m_BillingID = 6611; // Open billing ID 6611
hr = rs.OpenAll(); // (Open also executes the command)
hr = rs.MoveFirst(); // Move to the first row and print it
_tprintf_s(_T("First name: %s, Last Name: %s, Customer ID: %d, Postal Code: %s\n"),
rs.m_ContactFirstName, rs.m_L_Name, rs.m_CustomerID, rs.m_PostalCode);
// Close the first command execution
rs.Close();
rs.m_BillingID = 3333; // Open billing ID 3333 (a new customer)
hr = rs.Open(); // (Open also executes the command)
hr = rs.MoveFirst(); // Move to the first row and print it
_tprintf_s(_T("First name: %s, Last Name: %s, Customer ID: %d, Postal Code: %s\n"),
rs.m_ContactFirstName, rs.m_L_Name, rs.m_CustomerID, rs.m_PostalCode);
// Close the second command execution;
// Instead of the two following lines
// you could simply call rs.CloseAll()
// (a wizard-generated method):
rs.Close();
rs.ReleaseCommand();
CoUninitialize();
}
Requirements
Header: atldbcli.h