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Creating Databases for Web Applications
State capitals quiz: demonstrates parallel structures AND multi-purpose php files 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. Catch up on postings oh php and MySql. There is a new assignment. Note: you can use regular expressions in your simple quiz.
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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
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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
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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. This is how it is done in php. Do try for the extra credit. Must be unique.
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State capital quiz 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 Obvious choice for parallel structures because there are pairs of data. (Of course, this quiz requires exact answers, and doesn't accept abbreviations or minor mis-spellings).
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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 The statecapitals.php file is the data. Call it a data bank.
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State capitals storyboard
Include file: statecapitals.php statecapquiz.php statecapquizcheck.php Notice: no html files
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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
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statecapitals.php <?php $states = Array(); $capitals = Array();
$states[]="Alabama"; //adds to array $capitals[]="Montgomery"; $states[]="Alaska"; $capitals[]="Juneau"; … I wrote all this!!!
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statecapquizask.php <h1>State Capital Quiz </h1><p>
<html> <head> <title>State capitals quiz: check</title> </head> <body> <h1>State Capital Quiz </h1><p> <?php if ($saywhich){ include("statecapitals.php"); $which=$_GET['which']; $choice=rand(0, sizeOf($states)-1); If $saywhich is true, meaning it was set, then $which will determine what type of question to ask
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$state = $states[$choice];
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=$choice>\n"); print("<input type='submit' value='Submit Answer'>"); print("</form>\n"); } Why should I NOT have used method=get ???
![$state = $states[$choice];](http://slideplayer.com/slide/12166477/71/images/11/%24state+%3D+%24states%5B%24choice%5D%3B.jpg "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 ); } Why should I NOT have used method=get")
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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 { $capital = $capitals[$choice]; print( $capital is the capital of which state <br> );](http://slideplayer.com/slide/12166477/71/images/12/else+%7B+%24capital+%3D+%24capitals%5B%24choice%5D%3B+print%28+%24capital+is+the+capital+of+which+state+%3Cbr%3E+%29%3B.jpg "print( <form action= statecapquizcheck.php method= get >\n ); print( <input type= text name= state ><br>\n ); print( <input type= hidden name= which value=$which>\n ); print( <input type= hidden name= choice value=$choice>\n ); print( <input type= submit value= Submit Answer > ); print( </form>\n ); } }")
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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>
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statecapquizcheck.php <html> <head> <title>State capitals quiz: check</title> </head> <body> <?php include('statecapitals.php'); $choice=$_GET['choice']; $which=$_GET['which']; $correctstate=$states[$choice]; $correctcapital=$capitals[$choice];
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if ($which=='state') { if ($capital == $correctcapital) { print("Correct! $correctcapital is the capital of $correctstate!"); print("<p><a href='statecapquizask.php'>Play again </a>"); }
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print("<input type='text' name='capital'><br>\n");
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"); } }
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else { if ($state == $correctstate) { print("Correct! The capital of $correctstate is $correctcapital!"); $saywhich='false'; print("<p><a href='statecapquizask.php'>Play again </a>"); }
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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"); } } ?>
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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 { $capital = $capitals[$choice]; print( $capital is the capital of which state <br> );](http://slideplayer.com/slide/12166477/71/images/19/else+%7B+%24capital+%3D+%24capitals%5B%24choice%5D%3B+print%28+%24capital+is+the+capital+of+which+state+%3Cbr%3E+%29%3B.jpg "print( <form action= statecapquizcheck.php method= get >\n ); print( <input type= text name= state ><br>\n ); print( <input type= hidden name= which value=$which>\n ); print( <input type= hidden name= choice value=$choice>\n ); print( <input type= submit value= Submit Answer > ); print( </form>\n ); } }")
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print("<form action='statecapquizask.php' method='get'>\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> So why did I use method=get all those times??? See next.
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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… Answer: pedagogical reasons. I wanted you to see what the form was producing.
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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 Opportunities for improvement
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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-tries some other quiz! Do this!
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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. You will need to upload your 3 files.
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