Amp and higher computing science

Charlie Love
Education Support Officer
Aberdeen City Council
@charlie_love

Software development using Server-
side scripting
• an integrated approach to Higher Computing
Science.
• approaches to increase teaching time
• reduce the assessment
• strategies for integrated delivery blending
components of the SDD and ISDD units
• use contemporary web technologies:
Apache/Mysql/PHP/JavaScript

Higher Computing Science
Software Design
and
Development
Information
Systems Design
and
Development
Assessment

Assessment
Information
Systems Design
and Development
Software Design
and Development Integrating the delivery of
units using a server side
scripting language
will increase teaching time
and decrease time take for
assessment

Get *AMP on your computers
• Education Scotland Blog post with information
• http://glo.li/edscot-amp
• MAMP
• EasyPHP
• XAMMP
• WAMP
• etc.

Building solutions
• Agile methodologies
• Interative prototyping
• Design->Build->Test->Repeat
• Working code
• Limited Feature Set -> Expanded Feature Set

sub-programs/routines
defined by their name and arguments (inputs
and outputs)
• PHP uses functions which typically return a
single value.
• Use of &parameter passes values by
reference to the PHP function (essentially
creating a subprogram)

including parameter passing (value
and reference, formal and actual)
function read_users( $file, &$user_id, &$user_name,
&$user_image, &$password_string, $index ) {
$textline = fgets($file);
$textarray = explode(',',$textline);
$user_id[$index] = trim($textarray[0])
$user_name[$index] = trim($textarray[1]);
$user_image[$index] = trim($textarray[2]);
$password_string[$index] = trim($textarray[3]);
}

methods
• methods are subroutines associated with an
object
• they have access to the objects data.
• PHP includes support for object oriented
programming
• Use the MySQL API to show methods on
database objects

If ($result = $mysqli->query
("SELECT * FROM user WHERE user_id = '" .
$login_user_id . "'"))
{
$obj = $result->fetch_object();
$user_id = $obj->user_id;
$user_name = $obj->user_name;
$user_image = $obj->user_image;
$result->close();}

Data types and structures
• string
• numeric
(integer and real)
• Boolean
$mysting=“Some
text”;
$integer = 12;
$real =15.232;
$is_set = true;

• Records - Implement as an array of objects
class Owner
{
public $year;
public $measure;
public $month;
public $name;
}
$names = array('Lars', 'James', 'Kirk', 'Robert');
for ($i = 1 ; $i <= 3 ; $i++) {
$owner = new Owner();
$owner->year = 2012;
$owner->measure = $i;
$owner->month = rand(1,12);
$owner->name = array_rand($names);
$owners[] = $owner;
}

• sequential files (open, create, read, write,
close)
• fopen(filename, mode)
– Creates and/or opens file
– Mode is read and/or write and moves file pointer
to start or end of file.
– http://www.php.net/manual/en/function.fopen.p
hp
• fwrite($file, $textline);
– $file is the file handle from opening the file
– $textline is the line of text to be written
• fgets($file)
– Reads line of text from the file
• fclose($file) – close file

Standard Algorithms
• input validation (server side) / server-side
validation of online form data
– Set up form in html
– Process and validate form on submission
– Processing happens at server
– User interaction is required to create validation
loop

<?php
$username="”;
if (isset($_GET[’username'])) {
$error_found = false;
$message = "username is accepted”;
$username = $_GET[’username’];
if(strlen($username) < 8 ) {
$error_found = true;
$message = “Enter 8 or more characters”;
}
echo "<div>" . $message . "</div>";
}
if (($error_found) || (!isset($error_found))) { //show form if err found or 1st visit
?>
<form action="<?php echo $_SERVER[‘PHP_SELF’];?>" method="get">
<input type="text" name="username" value="<?php echo $username;?>">
<input type="submit" value="Submit" name="update"/>
</form>
<? php } ?>

Linear search
• linear search
function linear_search($needle, $haystack) {
for($i = 0; $i < count($haystack); $i++) {
if ($needle == $i)
return true;
}
return false;
}
$haystack = array(1,2,3,4);
$needle = 3;
$found = linear_search($needle, $haystack);

Finding minimum and maximum
Inbuilt max and min functions do it out of the box
function findmax($array_of_values) {
$current_max = $array_of_values[0];
for($i = 1; $i < count($array_of_values); $i++) {
if ($array_of_values[$i] > $current_max) {
$current_max = $array_of_values[$i];
}
}
return $current_max;
}
$my_array= array(12,25,23,14);
$biggest_number = findmax($my_array);

count occurrences
function count_values($val_to_count, $array_of_values) {
$counter = 0;
for($i = 0; $i < count($array_of_values); $i++) {
if ($array_of_values[$i] == $val_to_count) {
$counter++;
}
}
return $counter;
}
$my_array= array(12,25,23,14,72,83,12,12,63,25,14);
$count_of_values = count_values(12, $my_array);

Coding (ISDD)
• scripting (database/web pages)
• client-side scripting
• server-side scripting
• server-side validation of online form data

Structures and Links (Database)
• MySQL
• phpMyAdmin - Database front end
– Can be used to generate SQL for coding
– Web based – simplifies database management

Structures and Links (Web)
• PHP, HTML, CSS, JavaScript all play well together
<html>
<head>
<title><?php echo $title;></title>
<style>
hr {color:sienna;}
p {margin-left:20px;}
body {background-image:url(“bg.gif");}
</style>
<script>
function show_message() {
alert(“hello there”);
}
</script>
<body onLoad=“show_message();”>
….

PHP and MySQL
//connect to the database using mysqli API
$mysqli = new mysqli("localhost", "root", "root",
”mydatabase");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" .
$mysqli->connect_errno . ") "
. $mysqli->connect_error;
die;
}

Run a query and retrieve results
if ($result = $mysqli->query("SELECT * FROM my_table
WHERE field_id = '" . $field_id . "'"))
{
$obj = $result->fetch_object();
$my_field_id = $obj->field_id;
$my_field1 = $obj->field1;
$my_field2 = $obj->field2;
/* free result set */
$result->close();
}

Write to the database
$sql = mysqli('localhost','user','password','database');
$name = $_POST['name'];
$age = $_POST['age'];
$email = $_POST['email'];
$query = $sql->prepare("INSERT INTO `tablename`
VALUES ('?','?','?');");
$query->bind_param("sis",$name,$age,$email);
$query->execute();

Relationships in MySQL
Implemented using queries
SELECT * FROM table1, table2
WHERE table2.id = table1.hid
id field
12 Harry
13 Sally
14 Joe
15 Kirsty
id field hid
3232 sweets 12
3233 candy 12
3234 chocolate 12
3235 popcorn 13
3236 soup 13
table1 table2

Search in MySQL
Implemented using queries
WHERE table1.id = 12;
WHERE table1.field LIKE “%Joe%”
AND WHERE table2.id = table1.hid ;

Assessment
• You need to show that the candidate has
achieve all the Assessment Standards
• SDD Outcome 2 and ISDD Outcome 1 can be
assessed in the same exercise
• Alternative evidence can be gathered as part
of learning and teaching
• SDD Outcome 1 for part of this as well

Higher Assignment
• Assignment 1: Coding + Database (Diving
Championship – available now)
• Assignment 2: Server Side Scripting
– File handling
– Linear Search
– Server side scripting
– Online database integration
• Assignment 3: Client Side Scripting
– CSS
– Browser based

Blog: http://charlielove.org
Twitter: @charlie_love

Amp and higher computing science

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