Immediate Execution
To execute an SQL statement immediately, use the member function
IldRequest::execute, which takes two arguments:
The first argument is the SQL statement string.
The second argument,
rowCount, is optional. If specified, it must be a valid pointer to an
IlInt variable, which will be set to the number of processed rows if the statement is
delete,
insert, or
update.
Note: rowCount is zero after a select query is executed. For performance reasons, most RDBMSs do not “look ahead” to set this value for a query. |
Once the call to
IldRequest::execute succeeds, you can retrieve the execution status via the member function
IldRequest::getStatus. This member function returns the number of processed rows if the SQL statement is
delete,
insert, or
update. If it is a
select statement, the returned value is the number of rows actually fetched —namely 0 when the execution has just been completed.
Note: An SQL statement that is to be executed immediately must not contain any parameters. |
If the execution fails, the returned value, usually -1, is not meaningful.
{
if (!request->execute(queryBuffer))
IldDisplayError("Executing: ", request);
else {
if (!request->fetch())
IldDisplayError("Fetching: ", request);
else if (request->hasTuple())
// Loop with two levels, since ODBC, Sybase, and MS SQL Server
// can have several result sets for one command.
do {
if (request->getColCount()) {
IldPrintTuple(request, IldNames);
IldPrintTuple(request, IldSeparators);
IldPrintTuple(request);
while (request->fetch().hasTuple())
IldPrintTuple(request);
cout << endl;
if (request->isErrorRaised())
IldDisplayError("Fetching: ", request);
}
} while (request->fetch().hasTuple());
else if (request->getColCount()) {
IldPrintTuple(request, IldNames);
IldPrintTuple(request, IldSeparators);
cout << endl << "No row found." << endl;
}
else if ((count = request->getStatus()) > 0)
cout << count << " modified line(s)" << endl;
}
}
It is also possible to get the attributes of the returned rows from the result set, using the following member functions:
If the SQL statement is
select, you can retrieve the rows using the member function
IldRequest::fetch. When used after execution of any other SQL statement, this member function is ineffective, but no error is raised.
Version 5.8
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