Lecture 23 Robb T. Koether

PHP QueryingLecture 23

Robb T. Koether

Hampden-Sydney College

Fri, Mar 8, 2013

Robb T. Koether (Hampden-Sydney College) PHP Querying Fri, Mar 8, 2013 1 / 22

1 Searching the Database

2 Deleting from the Database

3 Inserting into a Database

4 Updating the Database

5 Assignment


Outline





5 Assignment


Searching the Database

Suppose that we want to search the employees table of thecompany database for a specific employee.We must

Use a form to get the employee’s Social Security number (theprimary key).Send it to a PHP program.Query the database for that Social Security number.Report the results.


Getting the Social Security Number

Getting the Social Security Number<form method="POST" action="find_emp.php">Enter the Social Security number of the employeethat you wish to find.<br/><input type="text" name="ssn"><br/><input type="submit" value="Find Employee"/><input type="reset"/></form>



Search the Database$ssn = $_POST[’ssn’];$query = "SELECT fname, lname FROM employees"

. " WHERE ssn=’$ssn’";$result = mysql_query($query) or die(...);if (mysql_num_rows($result) == 0)

echo "Employee with ssn $ssn was not found";else{

$row = mysql_fetch_array($result);$fname = $row[’fname’];$lname = $row[’lname’];echo "$fname $lname was found";

}



Now suppose that we want to report the dependents of thatemployee.We must

Search for search the dependents table of the employee’s SocialSecurity number.Retrieve the names of his dependents.Report the dependents’ names.



Search the Database$query = "SELECT dep_name FROM dependents"

. " WHERE ssn=’$ssn’";$result = mysql_query($query) or die(...);if (mysql_num_rows($result) == 0)

echo "$fname $lname has no dependents.";else{

echo "Dependents of $fname $lname are:<br/>";while ($row = mysql_fetch_array($result))

echo "$row[’dep_name’]<br/>";}


Outline





5 Assignment


Deleting from the Database

Suppose that we want to delete an employee from the database.We must

Select the employee from a list.Delete the employee’s tuple from the employees table.Delete the employee’s tuples from the dependents and workstables.



In the HTML Form<form method="POST" action="del_emp.php">Select the employee to be deleted:<select name="ssn"><?php$query = "SELECT fname, lname, ssn FROM employees";$result = mysql_query($query) or die(...);while ($row = mysql_fetch_array($result)){

$fname = $row[’fname’];$lname = $row[’lname’];$ssn = $row[’ssn’];echo "<option value=’$ssn’>$fname $lname</option>";

}?></select><input type="submit" value="Delete Employee"/><input type="reset"/></form>



In the filedel_emp.php$ssn = $_POST[’ssn’];$query = "DELETE FROM employees WHERE ssn=$ssn";mysql_query($query) or die(...);$query = "DELETE FROM dependents WHERE ssn=$ssn";mysql_query($query) or die(...);$query = "DELETE FROM works WHERE ssn=$ssn";mysql_query($query) or die(...);echo "The employee has been deleted";


Outline





5 Assignment


Inserting into a Database

We will use the company database for our examples.Suppose that we want to add an employee to the database.We must get from the user the employee’s

First and last names.Social Security number.Sex.Birthday.Salary.Department.

Then insert these data into the employees table.


Inserting into the Database

Insert into the Database$fname = $_POST[’fname’];$lname = $_POST[’lname’];$ssn = $_POST[’ssn’];$sex = $_POST[’sex’];$bdate = $_POST[’bdate’];$salary = $_POST[’salary’];$dept = $_POST[’dept’];$query = "SELECT * FROM employees WHERE ssn=’$ssn’";$result = mysql_query($query) or die(...);

We must get the form information and find out whether the employee isalready in the database.


Inserting into the Database

Insert into the Databaseif (mysql_num_rows($result) > 0)

echo "$fname $lname is already in the database";else{

$query = "INSERT INTO employees". " VALUES (’$fname’, ’$lname’, ’$ssn’, ’$sex’,". " ’$bdate’, $salary, $dept)";

mysql_query($query) or die(...);echo "$fname $lname has been added to the database";

}

If he is not already in the database, then add him.


The HTML Form

In the HTML form, we needText boxes for the first name, last name, Social Security number,and salary.Select elements for the sex, birthday, and department.Select elements for the birthday (month, day, year).Select elements or radio buttons for the sex and department.

We can fill the sex and birthday choices with the obvious values.For the department, we should construct the list of options fromthe database, using the departments table.


Creating a Select List of Departments

Create a Select List of Departments<select name="dept"><?php$query = "SELECT dname, dept FROM departments";$result = mysql_query($query) or die(...);while ($row = mysql_fetch_array($result)){

$dname = $row[’dname’];$dept = $row[’dept’];echo "<option value=’$dept’>$dname</option>";

}?></select><br/>


Outline





5 Assignment


Updating the Database

We want to update the data for an employee.We must

Select the employees name and Social Security number from theemployees table.Display the current employee information.Allow the information to be edited.Save the changes.


Outline





5 Assignment


Assignment

AssignmentVisit the W3Schools website

http://www.w3schools.com/html/Visit the sections labeled “PHP MySQL Intro” through ”PHPDELETE.”

Visit the PHP websitehttp://php.net/manual/en/book.mysql.php

and check out the functions that we used.


http://www.w3schools.com/html/

http://php.net/manual/en/book.mysql.php

Lecture 23 Robb T. Koether

Documents

Transcript of Lecture 23 Robb T. Koether