PHP+MySQL Integration

PHP+MySQL Integration

Connecting to databases• One of the most common tasks when working

with dynamic webpages is connecting to a database which holds the content of the page

• PHP has several libraries that allows for communication with many different databases

• Some of these libraries have variations in the commands

• We will be using the mysql library• Most functions start with mysql_ and then the

name of the function

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Opening a connection

• You will need:– The address to the database server– A username with privileges to access the table you

require– The username associated password

• Optionally:– The name of the database you are connecting

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Connection Sequence

• mysql_connect(host, username, password): returns a link to the host using username and password authentication.

• Usage:– $conn=mysql_connect(‘localhost’, ‘myusername’,’MyP455w0rd’)

• mysql_select_db(database,link): selects a database from the connection in link

• Usage:– mysql_select_db(‘db_name’,$conn);

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Executing Queries

• mysqli_query(link, query) is used to run a query on the database server. Required the link and the query string. Returns a result object.

• Usage:– $result= mysql_query(“SELECT * from directory”, $conn);

• Queries can be constructed as strings and then the string variable can be used on the mysql_query command:– $query="select * from directory";– $result = mysql_query($query,$link) or die("could not

execute:".mysql_error());

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Working with the results from the query

• Result sets are objects. They point to places in memory where the query returned values exist

• Result set are NOT the individual rows from the query• You can think of a result set as the TABLE that holds

the results• You need to read the rows from that table individually– $row=mysql_fetch_array($result);

• Using this function, the array returned can be either numerically indexed or associative!

• If there are no more rows, the function returns FALSE

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Keeping it tidy• Once you have completed your work with the

database, there are two things you should do:– Free the results– Close the connection to the server.

• Freeing the results can be optional: On closing the connection, the results are automatically freed

• If you are planning to run further queries on the same connection, it is good practice to free the previous result set.– mysql_free_result($result);

• To close the connection you use– mysqli_close($conn);

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Working with databases – key steps

• Design the DB – Create the DB on PHPMyAdmin or MySQL command

• Design and Create the HTML• Create a connection• Select the table• Run the query• Verify Insert/Fetch the rows/Do other SQL

associated tasks• Display Results as needed• Close the connection

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Database Design and Creation

Create database ‘hospital’, add a table ‘discharge’ with appropriate fields – patient id, name, appointment type, admission ward, xray examination, mri scan, cat scan, eye test, hearing test, and date (to capture todays date)

hospitaldischarge(patid,name,appointment,ward,xray,mri,cscan,eye,hearing,date)

Data details

Field Type Comment

patid int(11) NN AI PK Primary Key Index

name varchar(45) Patient Full Name

appointment varchar(11) type of appointment:GP, Specialist or Surgery

ward char(2) Admitted to ward? No, or ward A,B or C

xray char(3) x-rays taken? YES,NO

mri char(3) mri carried out? YES,NO

cscan char(3) CAT scan carried out? YES,NO

eye char(3) eye test carried out? YES,NO

hearing char(3) hearing test carried out? YES,NO

date date date of discharge: format YYYY-MM-DD as text

• Go ahead and create the database and table using PHPMyAdmin or MySQL command Prompt

Data capture form

<form action="process.php" method="get" name="discharge">

Patient Name: <input type="text" name="name" /><br /><hr />Appointment type<br /><select name="appointment"><option value="GP">General Practicioner</option><br /><option value="Specialist">Specialist</option><br /><option value="Surgery">Surgery</option><br /></select>

link to php script fileuse get to check form is working correctpost could also be used, user choice

table name

3 options for app type

Radio buttonAdmission to Wards:<br /> <label> <input type="radio" name="ward" value="No" /> No Ward</label> <br /> <label> <input type="radio" name="ward" value="A" /> Ward A</label> <br /> <label> <input type="radio" name="ward" value="B" /> Ward B</label> <br /> <label> <input type="radio" name="ward" value="C" /> Ward C</label> <br /><hr />

4 options via radiobuttons, only one canbe selected on form

Checkboxes

Treatments Undertaken:<br /><input type="checkbox" name="xray" value="yes" />X-Ray Treatment<br /><input type="checkbox" name="mri" value="yes" />MRI Scan<br /><input type="checkbox" name="cscan" value="yes" />CAT Scan<br /><input type="checkbox" name="eye" value="yes" />Eye Test<br /><input type="checkbox" name="hearing" value="yes" />Hearing Test<br /><hr />

5 options, any can be selected on form

Submit/reset button

<input type="submit" value="Submit Form" /><input type="reset" value="Reset Form" /></form>

PHP-process.php

<?php$id = $_GET['patid'];$name = $_GET['name'];$app = $_GET['appointment'];$ward = $_GET['ward'];

$string

single option data passing

$_POST option also viable, keep consistent withprevious use

Open a new file, save as process.php, keep on same directory as html file

Checkbox data selection

if (isset($_GET['xray'])) {$xray = $_GET['xray'];} else {

$xray = "No";}

Note: This code needs to be repeated for every checkbox variable passed as a parameterthe variables used are:$mri, $cscan, $eye, $hearing

checkboxes allow multiple options

if not checked, it will not pass the parameter (not set)

if passed the default is set to ‘yes’

so if not passed, we need to assigna value to the respective variable that will go into the database

print "Name:".$name."<br />";print "Appointment:".$app."<br />";print "Ward:".$ward."<br />";print "X-Ray:".$xray."<br />";print "MRI:".$mri."<br />";print "CSCAN:".$cscan."<br />";print "EYE:".$eye."<br />";print "HEARING:".$hearing."<br />";

print used to check fields are beingpassed and captured in the page

Database connection

$link = mysql_connect('localhost','student','student') or die(mysql_error());mysql_select_db('hospital',$link);

Current date selection

$querydate = "SELECT CURDATE() as Today";$result1 = mysql_query($querydate,$link) or die(mysql_error());$row = mysql_fetch_assoc($result1);$today = $row['Today'];

This script demonstrates how the current datecan be obtained from the MySQL server using the appropriate DATE query

The parameter being queried (date)does not have an index in the array,so we need to use the alias “AS” to assignan index that we can use to retrieve fromthe result array

INSERT data

$query = "INSERT INTO discharge VALUES (NULL,'$name','$app','$ward','$xray','$mri','$cscan','$eye','$hearing','$today')";$result = mysql_query($query,$link) or die(mysql_error());$affected = mysql_affected_rows($link);

if ($affected >0) {echo "success";} else {echo "fail";}

detects affected rows in the queryin this case 1 row was INSERTED so$affected=1 if the insert was successful

generates my-sql error causes

Query to insert all data from html form + date obtained from previous query

Selection to display all

$query3 = "SELECT * FROM discharge";$result3 = mysql_query($query3,$link) or die(mysql_error());$row3 = mysql_fetch_assoc($result3);?>

This is another query to retrieve all the datafrom the table discharge

Table design for results

<table width="200" border="1"> <tr> <th scope="col">Patient ID</th> <th scope="col">Patient Name</th> <th scope="col">Appointment Type</th> <th scope="col">Admitted to Ward</th> <th scope="col">X-Ray</th> <th scope="col">MRI</th> <th scope="col">Cat Scan</th> <th scope="col">Eye Test</th> <th scope="col">Hearing Test</th> <th scope="col">Date Discharged</th> </tr>

Results

<tr> <td><?php echo $row3['patid']; ?></td> <td><?php echo $row3['name']; ?></td> <td><?php echo $row3['appointment']; ?></td> <td><?php echo $row3['ward']; ?></td> <td><?php echo $row3['xray']; ?></td> <td><?php echo $row3['mri']; ?></td> <td><?php echo $row3['cscan']; ?></td> <td><?php echo $row3['eye']; ?></td> <td><?php echo $row3['hearing']; ?></td> <td><?php echo $row3['date']; ?></td> </tr></table>

$row is an associative array containing the results,the index of the array are the fields in the database

do …. while loop

<?php do { ?> <tr> <td><?php echo $row3['patid']; ?></td> <td><?php echo $row3['name']; ?></td> <td><?php echo $row3['appointment']; ?></td> <td><?php echo $row3['ward']; ?></td> <td><?php echo $row3['xray']; ?></td> <td><?php echo $row3['mri']; ?></td> <td><?php echo $row3['cscan']; ?></td> <td><?php echo $row3['eye']; ?></td> <td><?php echo $row3['hearing']; ?></td> <td><?php echo $row3['date']; ?></td> </tr><?php } while ($row3=mysql_fetch_assoc($result3)); ?></table>

DO-WHILE Loopneeded to display all the results of the database

Close connection

<?phpmysql_close($link);?>

Places where things can go wrong

• Creating a connection– Server unreachable/offline– Wrong username/password combination

• Selecting the table– Table does not exist– User without privileges for that table

• Running the query– Syntax errors– Empty result set

• Fetching results– Misusing the array

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