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Re: OleDB + parameters = problem [message #19812 is a reply to message #19806] Fri, 23 January 2009 11:52 Go to previous messageGo to previous message
mirek is currently offline  mirek
Messages: 14291
Registered: November 2005
Ultimate Member
OK, you have been proved right w.r.t. prepared statements and speed, at least with MSSQL:

void Benchmark()
{
	Sql sql;
	sql * Select(ID).From(SUBJECT);
	Vector<int> id;
	while(sql.Fetch())
		id.Add(sql[0]);
	for(int i = 0; i < id.GetCount(); i++) {
		RTIMING("Unprepared");
		sql % Select(TEXT).From(SUBJECT_ATTR).Where(ATTR == "NAME" && SUBJECT_ID == id[i]);
	}
	sql.SetStatement("select TEXT from SUBJECT_ATTR where ATTR = ? and SUBJECT_ID = ?");
	for(int i = 0; i < id.GetCount(); i++) {
		RTIMING("Prepared");
		sql.Run("NAME", id[i]);
		sql.Fetch();
	}
}



TIMING Prepared       : 79.99 ms - 273.94 us (80.00 ms / 292 ), min:  0.00 ns, max:  1.00 ms, nesting: 1 - 292
TIMING Unprepared     : 483.99 ms -  1.66 ms (484.00 ms / 292 ), min:  0.00 ns, max: 15.00 ms, nesting: 1 - 292


Well, SqlExp cache will be fun Smile Thanks for makeing me aware about this.

Mirek
 
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