Scalable Alternative

Another possibility is that we can just get all the questions and set the internal pointer to a random row. While it does require a large space for storing the result, this solution will work better if our QuID s have a lot of holes, if questions are often deleted, or if they are entered in nonsequential order. The code necessary follows the logic in Figure 13.3 and looks like this:

Figure 13.3. Alternative Linear QuID Selection Method


 //The only portion of this code that changed was the constructor function Question( ) {   MySQL_connect('', 'bigfun', '[REDACTED]');   MySQL_select_db('bigfun');   $res = MySQL_query ("select QuID from Questions" );   $WhichRow = rand(0,MySQL_num_rows($res)-1);   $WhichQuid = MySQL_result($res,$WhichRow,0);   $res = MySQL_query ("select * from Questions where QuID = $WhichQuid" );   $sqlquestion = MySQL_fetch_array ($res );   $sqlQuid = $sqlquestion["QuID"];   $this->Q = $sqlquestion["Q"];   $this->idkey= $sqlquestion["QuID"];   MySQL_free_result($res);   $res = MySQL_query ("select * from Answers where WhichQuestion =          $sqlQUid");   $numrows = MySQL_num_rows($res);   for($i=0;$i<$numrows;$i++) {    $temp = MySQL_fetch_array($res);    array_push ($this->A , $temp["AnswerChoice"]);   } return $this; //     } 

No loop, cleaner flowchart.

Only a little bit of the code was changed, the part that selected the QuID used.

 $res = MySQL_query ("select QuID from Questions" ); 

Get all the QuID s of all the questions. Load them all into RAM.

 $WhichRow = rand(0,MySQL_num_rows($res)-1); 

Choose a random row of data. The rows are contiguous and zero-based . There are MySQL_num_rows($res) of them. The bounds on rand are inclusive.

 $WhichQuid = MySQL_result($res,$WhichRow,0); 

This code selects a field; specifically , it selects the QuID in the randomly selected row.

 $res = MySQL_query ("select * from Questions where QuID = $WhichQuid" ); 

This code retrieves the information about the Question whose QuID we have chosen . The rest of the code is the same between the two versions.

Flash and XML[c] A Developer[ap]s Guide
Flash and XML[c] A Developer[ap]s Guide
ISBN: 201729202
Year: 2005
Pages: 160 © 2008-2017.
If you may any questions please contact us: