iming differences that occur between the execution of repeated raw queries
The following code tests the timing differences that occur between the execution of repeated raw queries and repeated calls to prepared statements:
public class PreparedStatements
{
public static void main(String[] args)
{
if (args.length < 5)
{
printUsage();
return;
}
String vendor = args[4];
DriverUtilities.loadDrivers();
if (!DriverUtilities.isValidVendor(vendor))
{
printUsage();
return;
}
String driver = DriverUtilities.getDriver(vendor);
String host = args[0];
String dbName = args[1];
String url = DriverUtilities.makeURL(host, dbName, vendor);
String username = args[2];
String password = args[3];
boolean print = false;
if ((args.length > 5) && (args[5].equals("print")))
{
print = true;
}
Connection connection =
ConnectionInfoBean.getConnection(driver, url, username, password);
if (connection != null)
{
doPreparedStatements(connection, print);
doRawQueries(connection, print);
}
try
{
connection.close();
}
catch(SQLException sqle)
{
System.err.println("Problem closing connection: " + sqle);
}
}
private static void doPreparedStatements(Connection conn, boolean print)
{
try
{
String queryFormat =
"SELECT id FROM music WHERE price < ?";
PreparedStatement statement =
conn.prepareStatement(queryFormat);
long startTime = System.currentTimeMillis();
for(int i=0; i<100; i++)
{
statement.setFloat(1, i/4);
ResultSet results = statement.executeQuery();
if (print)
{
showResults(results);
}
}
long stopTime = System.currentTimeMillis();
double elapsedTime = (stopTime - startTime)/1000.0;
System.out.println("Executing prepared statement " +
"100 times took " +
elapsedTime + " seconds.");
}
catch(SQLException sqle)
{
System.err.println("Error executing statement: " + sqle);
}
}
public static void doRawQueries(Connection conn, boolean print)
{
try
{
String queryFormat =
"SELECT id FROM music WHERE price < ";
Statement statement = conn.createStatement();
long startTime = System.currentTimeMillis();
for(int i=0; i<100; i++)
{
ResultSet results =
statement.executeQuery(queryFormat + i/4);
if (print)
{
showResults(results);
}
}
long stopTime = System.currentTimeMillis();
double elapsedTime = (stopTime - startTime)/1000.0;
System.out.println("Executing raw query " +
"100 times took " +
elapsedTime + " seconds.");
}
catch(SQLException sqle)
{
System.err.println("Error executing query: " + sqle);
}
}
private static void showResults(ResultSet results) throws SQLException
{
while(results.next())
{
System.out.print(results.getString(1) + " ");
}
System.out.println();
}
private static void printUsage()
{
System.out.println("Usage: PreparedStatements host " +
"dbName username password " +
"vendor [print].");
}
}
Question :explain the key output of above code
please help me to solve this question.
thanks
honey sachdeva
