This function quits execution of a command you've passed to the server. It's relevant only when you're in asynchronous mode.
nSuccess = SQLCancel( nConnectionHandle )As far as we can tell, SQLCancel() always returns 1 as long as you give it a valid connection handle. It doesn't matter if there's actually something to cancel, or even if you're in asynchronous mode.
Use this function when you've started a process and realize that it's not such a good idea. We can think of a couple of handy ways to use this. For example, you might set up a timer and cancel after the specified time has elapsed. Or you might put up a message to the user indicating what's happening and including a Cancel button. If the user presses Cancel, you use SQLCancel() to kill the process.
nHandle = SQLConnect("Northwinds")
= SQLSetProp(nHandle, "Asynchronous", .T.)
= SQLExec(nHandle, "Select * FROM Customers,Orders")
* Oh, my goodness, it has no join condition!
= SQLCancel(nHandle)