I am trying to run a query that will display in my browser when I click the button, but instead the results are just displayed from the beginning. I have the button set to post and my php file as the action but it seems to just run the code from the beginning. Here is what I have:
<?php
$host = "localhost";
$db = "cis475";
$user = "root";
$pw = "";
$conn = new mysqli ($host, $user, $pw, $db);
if($conn->connect_error) die($conn->connect_error);
$readAllQuery = "SELECT * FROM enrollment JOIN course ON enrollment.CourseID
= course.CourseID JOIN student ON enrollment.StudentID = student.StudentID";
$result = $conn->query($readAllQuery);
if (!$result) die($conn->error);
echo "<table border='1'>";
echo "<tr><td>EnrollmentID</td><td>Grade</td><td>EnrollmentSemester</td>
<td>CourseID</td><td>StudentID</td><td>Title</td><td>Credits</td>
<td>LastName</td><td>FirstMidName</td></tr>";
while ($row = mysqli_fetch_assoc($result)){
echo "<tr><td>{$row['EnrollmentID']}</td><td>{$row['Grade']}</td>
<td>{$row['EnrollmentSemester']}</td><td>{$row['CourseID']}</td><td>
{$row['StudentID']}</td><td>{$row['Title']}</td><td>{$row['Credits']}
</td>
<td>{$row['LastName']}</td><td>{$row['FirstMidName']}</td></tr>";
}
echo "</table>";
?>
<form method='post' action='readAll.php'>
<input type='submit' name='submit' value='Show All Enrollments'>
</form>
You need to see if 'something' is there (in this case, all you have is the submit) and then do the display....
<?php
if($_POST['submit']){
$host = "localhost";
$db = "cis475";
$user = "root";
$pw = "";
$conn = new mysqli ($host, $user, $pw, $db);
if($conn->connect_error) die($conn->connect_error);
$readAllQuery = "SELECT * FROM enrollment JOIN course ON enrollment.CourseID = course.CourseID JOIN student ON enrollment.StudentID = student.StudentID";
$result = $conn->query($readAllQuery);
if (!$result) die($conn->error);
echo "<table border='1'>";
echo "<tr><td>EnrollmentID</td><td>Grade</td><td>EnrollmentSemester</td>
<td>CourseID</td><td>StudentID</td><td>Title</td><td>Credits</td>
<td>LastName</td><td>FirstMidName</td></tr>";
while ($row = mysqli_fetch_assoc($result)){
echo "<tr><td>{$row['EnrollmentID']}</td><td>{$row['Grade']}</td>
<td>{$row['EnrollmentSemester']}</td><td>{$row['CourseID']}</td><td>
{$row['StudentID']}</td><td>{$row['Title']}</td><td>{$row['Credits']}
</td><td>{$row['LastName']}</td><td>{$row['FirstMidName']}</td></tr>";
}
echo "</table>";
}
?>
<form method='post' action='readAll.php'>
<input type='submit' name='submit' value='Show All Enrollments'>
</form>
Any code present in inside the program file will run upon execution, this is true for all languages, unless it is wrapped inside an if
or any other conditional statements; in which case the code enclosed in the conditional statement will only be executed if the condition is true
.
And thus to solve your issue, you'll need a conditional statement that checks if the form was submitted or not and if it was then execute the code that follows-
if(isset($_POST['submit'])){
$host = "localhost";
$db = "cis475";
$user = "root";
$pw = "";
$conn = new mysqli ($host, $user, $pw, $db);
if($conn->connect_error) die($conn->connect_error);
$readAllQuery = "SELECT * FROM enrollment JOIN course ON enrollment.CourseID = course.CourseID JOIN student ON enrollment.StudentID = student.StudentID";
$result = $conn->query($readAllQuery);
if (!$result) die($conn->error);
echo "<table border='1'>";
echo "<tr><td>EnrollmentID</td><td>Grade</td><td>EnrollmentSemester</td>
<td>CourseID</td><td>StudentID</td><td>Title</td><td>Credits</td>
<td>LastName</td><td>FirstMidName</td></tr>";
while ($row = mysqli_fetch_assoc($result)){
echo "<tr><td>{$row['EnrollmentID']}</td><td>{$row['Grade']}</td>
<td>{$row['EnrollmentSemester']}</td><td>{$row['CourseID']}</td><td>
{$row['StudentID']}</td><td>{$row['Title']}</td><td>{$row['Credits']}
</td><td>{$row['LastName']}</td><td>{$row['FirstMidName']}</td></tr>";
}
echo "</table>";
}
In this snippet, we use if
statement to check if variable $_POST['submit']
exists.
Here submit
with is the name of your form's submit button
Note: a $_POST
variable will only exist if the form was submitted, calling isset()
will return false
if the form wasn't submitted and as such your code inside { }
will not be executed on first load but will run upon submit.
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