creating databases for web applications
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Creating Databases for Web Applications. State capitals quiz Classwork: design a new quiz Homework: Make sure you can upload files and have MySQL database. Get a simple quiz working like the state capital quiz. Post unique source on REGULAR expressions. multi-purpose php files. - PowerPoint PPT PresentationTRANSCRIPT
Creating Databases for Web Applications
State capitals quiz: demonstrates parallel structures AND multi-purpose php files
Classwork: design a new quizHomework: Make sure you can upload files and have MySQL database. Get a simple quiz working like the
state capital quiz.Post unique source on REGULAR expressions.
multi-purpose php files
• Used to both – present a form and– check the input in a form.
• Replacement for html and php pair.• Advantages:
– don’t have to coordinate two files– less files to handle
• Disadvantages– need to include coding to make determination
Use of @ sign• The @ sign is used to suppress error messages.• We will use it in the code to test if something,
namely a form input, exists.– if it does, then control goes to the code for handling
the form– otherwise, control goes to the code for displaying the
form• Also use it to suppress an error when one input
is missing
rand
• Built-in php function.• Takes two arguments.• rand(a, b), a and b integers, returns
random value from a, … b.
• Check out shuffle, mt_rand. Extra credit posting opportunity to explain.
State capital quiz
• http://socialsoftware.purchase.edu/jeanine.meyer/statecapquizask.php
• Choose what to be asked– Note: how can this be worded better????
• Ask• Check the answer
– Give chance to try again or– Go back to get new question
State capitals quiz
• Implementation: three php files. Two of the php files call themselves and include the other file.– statecapitals.php
• This file is include[d] in the others. It sets up 2 parallel arrays holding the names of the states and the capital cities.
– statecapquizask.php• This is a multi-purpose file.
– statecapquizcheck.php• This is also a multi-purpose file. Checks answer. Allows for
another guess or goes back to statecapquizask.php
State capitals storyboard
statecapquiz.php
statecapquizcheck.php
Include file: statecapitals.php
Programming practices
• Parallel structures, in this case the array of states corresponding to the array of capitals, is a common programming device. Think of it as an alternative to a database or xml for very simple cases.
• Repeat: multi-purpose, self-referencing of php scripts is a common practice – benefits: reduces number of files. Information in one
place– negatives: the one file is more complex
statecapitals.php
<?php$states = Array();$capitals = Array();$states[]="Alabama"; //adds to array$capitals[]="Montgomery"; $states[]="Alaska";$capitals[]="Juneau";…
statecapquizask.php<html> <head> <title>State capitals quiz: check</title></head> <body>
<h1>State Capital Quiz </h1><p><?php$saywhich=@$_GET['saywhich'];if ($saywhich){ include("statecapitals.php"); $which=$_GET['which']; $choice=rand(0, sizeOf($states)-1);
if ($which=='state') { $state = $states[$choice]; print("What is the capital of $state?<br>"); print("<form action='statecapquizcheck.php'
method='get'>\n"); print("<input type='text' name='capital'><br>\n"); print("<input type='hidden' name='which'
value=$which>\n"); print("<input type='hidden' name='choice'
value=$choice>\n"); print("<input type='submit' value='Submit
Answer'>"); print("</form>\n"); }
else { $capital = $capitals[$choice]; print("$capital is the capital of which state?<br>");
print("<form action='statecapquizcheck.php' method='get'>\n");
print("<input type='text' name='state'><br>\n"); print("<input type='hidden' name='which' value=$which>\n");
print("<input type='hidden' name='choice' value=$choice>\n");
print("<input type='submit' value='Submit Answer'>");
print("</form>\n"); } }
else { print("Choose form of question: do you want to be given the
state or the capital?<br>"); print("<form action='statecapquizask.php' method='get'>\
n"); print("Ask <input type='radio' name='which'
value='state'>State"); print(" <input type='radio' name='which'
value='capital'>Capital\n"); print("<input type='hidden' name='saywhich' value='true'>\
n"); print("<input type='submit' value='Submit choice'>"); print("</form>"); } ?> </body> </html>
statecapquizcheck.php<html> <head> <title>State capitals quiz:
check</title> </head> <body><?phpinclude('statecapitals.php');$choice=$_GET['choice'];$state=@$_GET['state'];$capital=@$_GET['capital'];$which=$_GET['which'];$correctstate=$states[$choice];$correctcapital=$capitals[$choice];
if ($which=='state') { if ($capital == $correctcapital) { print("Correct! $correctcapital is the
capital of $correctstate!"); print("<p><a
href='statecapquizask.php'>Play again </a>");
}
else { print("WRONG!<p>\n"); print("<a href='statecapquizask.php'>New turn </a><p>\
n"); print("OR try again: What is the capital of $correctstate?
<br>"); print("<form action='statecapquizcheck.php' method='get'>\
n"); print("<input type='text' name='capital'><br>\n"); print("<input type='hidden' name='state' value=$state>\n"); print("<input type='hidden' name='which' value=$which>\
n"); print("<input type='hidden' name='choice' value=$choice>\
n"); print("<input type='submit' value='Submit Answer'>"); print("</form>\n"); } }
else { if ($state == $correctstate) { print("Correct! The capital of
$correctstate is $correctcapital!"); $saywhich='false'; print("<p><a
href='statecapquizask.php'>Play again </a>");
}
else {print("WRONG!<p>\n"); print("<a href='statecapquizask.php'>New turn </a><p>\n"); print("OR try again: $correctcapital is the capital of what
state?<br>"); print("<form action='statecapquizcheck.php' method='get'>\
n");print("<input type='text' name='state'><br>\n"); print("<input type='hidden' name='capital' value=$capital>\n"); print("<input type='hidden' name='which' value=$which>\n"); print("<input type='hidden' name='choice' value=$choice>\n"); print("<input type='submit' value='Submit Answer'>"); print("</form>\n"); } }?>
else { $capital = $capitals[$choice]; print("$capital is the capital of which state?<br>"); print("<form action='statecapquizcheck.php'
method='get'>\n"); print("<input type='text' name='state'><br>\n"); print("<input type='hidden' name='which'
value=$which>\n"); print("<input type='hidden' name='choice'
value=$choice>\n"); print("<input type='submit' value='Submit Answer'>"); print("</form>\n"); } }
else {print("Choose form of question: do you want to be given the
state or the capital?<br>");print("<form action='statecapquizask.php' method='get'>\n");print("Ask <input type='radio' name='which'
value='state'>State");print(" <input type='radio' name='which'
value='capital'>Capital\n");print("<input type='hidden' name='saywhich' value='true'>\
n");print("<input type='submit' value='Submit choice'>");print("</form>"); }?></body></html>
Reprise• if statements within if statements• php produces the appropriate html,
including the form element• The php is printing (producing) html. It is
not operating the quiz!• There are ways to enhance this program
– perhaps limit the number of re-tries– prevent browser from showing previous inputs– see next slide…
Note• Answer must be exact!• Sometimes this is not appropriate.• Consider NOT requiring exact case.
– Extra credit opportunity• Consider something else, such as inexact
spelling. What is close enough? How to measure?
• Use of regular expression is a way to present a pattern of answers as opposed to a set answer.
• Later: we will cover the use of LIKE as an operator in MySql statements
Classwork (teams)
Design simple quiz • like the state capital quiz, using parallel arrays
for questions and answers – Ideas?
OR• make significant enhancement to my quiz, like
adding scoring, limiting re-triesOR• some other quiz!
Homework
• Get your quiz working. Post link in posting to the General Discussion Forum.
• Research and post unique source on Regular expressions on moodle. We use regular expressions – to validate input and extract information from
input.– potential for quizzes.