PHP+MySQL Integration

1. PHP+MySQL Integration

2. 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

3. 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

4. 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);

5. 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());

6. 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

7. 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);

8. 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

9. 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) hospital discharge(patid,name,appointment,ward,xray,mri,cscan,eye,hearing,date)

10. Data details

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

12. Data capture form use get to check form is working correct post could also be used, user choice link to php script file <form action="process.php" method="get" name="discharge"> table name 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> 3 options for app type

13. Radio button Admission 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 radio buttons, only one can be selected on form

14. 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

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

16. PHP-process.php Open a new file, save as process.php, keep on same directory as html file single option data passing $_POST option also viable, keep consistent with previous use <?php $id = $_GET['patid']; $name = $_GET['name']; $app = $_GET['appointment']; $ward = $_GET['ward']; $string

17. Checkbox data selection 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 assign a value to the respective variable that will go into the database if (isset($_GET['xray'])) { $xray = $_GET['xray']; } else { $xray = "No"; } Note: This code needs to be repeated for every checkbox variable passed as a parameter the variables used are: $mri, $cscan, $eye, $hearing

18. 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 being passed and captured in the page

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

20. Current date selection This script demonstrates how the current date can be obtained from the MySQL server using the appropriate DATE query $querydate = "SELECT CURDATE() as Today"; $result1 = mysql_query($querydate,$link) or die(mysql_error()); $row = mysql_fetch_assoc($result1); $today = $row['Today']; The parameter being queried (date) does not have an index in the array, so we need to use the alias “AS” to assign an index that we can use to retrieve from the result array

21. INSERT data Query to insert all data from html form + date obtained from previous query $query = "INSERT INTO discharge VALUES (NULL,'$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";} generates my-sql error causes detects affected rows in the query in this case 1 row was INSERTED so $affected=1 if the insert was successful

22. Selection to display all This is another query to retrieve all the data from the table discharge $query3 = "SELECT * FROM discharge"; $result3 = mysql_query($query3,$link) or die(mysql_error()); $row3 = mysql_fetch_assoc($result3); ?>

23. 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>

24. Results $row is an associative array containing the results, the index of the array are the fields in the database <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>

25. 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 Loop needed to display all the results of the database

26. Close connection <?php mysql_close($link); ?>

27. 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