Data invoeren in meerdere/joined tabellen

<form action="med_insert.php" method="post">
	<fieldset>
	
	<p><label for="medicinename"><b>Medicine Name:</b></label> <input type="text" name="medicinename" id="medicinename" value="<?php if (isset($trimmed['medicinename'])) echo $trimmed['medicinename']; ?>" /></p>
	
	<p><label for="productiondate"><b>Production Date:</b></label> <input type="text" name="productiondate" id="productiondate" value="<?php if (isset($trimmed['productiondate'])) echo $trimmed['productiondate']; ?>" /></p>

	<p><b><label for="expirationdate">Expiration Date:</b></label> <input type="text" name="expirationdate" id="expirationdate" value="<?php if (isset($trimmed['expirationdate'])) echo $trimmed['expirationdate']; ?>" /> </p>
	
	<p><b><label for="medicineprise">Medicine price:</b></label> <input type="text" name="medicineprise" id="medicineprise" value="<?php if (isset($trimmed['medicineprise'])) echo $trimmed['medicineprise']; ?>" /> </p>
	
	<p><label for="medicinetypename"><b>Select medicine type:</b></label>
	<select name="medicinetypename">
	<option value="">---Select---</option>
		<?php
		require_once (MYSQL);
		$query = "SELECT * from medicinestype";
		$result = mysqli_query($dbc,$query);
		if(!$result){
			die ("query failed" . mysqli_error($dbc));	
		}
		while ($row = mysqli_fetch_assoc($result)){
				$medicinetype_id = $row['id'];
				$medicinetypename = $row['medicinetypename'];
			echo "<option value='$medicinetype_id'>{$medicinetypename}</option>";
		} 
		?>
	</select></p>	
	<p><label for="suppliername"><b>Delivered by supplier:</b></label>
	<select name="suppliername">
		<option value="">---Select---</option>
		<?php

		$query2 = "SELECT * from suppliers";
		$result2 = mysqli_query($dbc,$query2);
		if(!$result2){
			die ("query failed" . mysqli_error($dbc));	
		}
		while ($row = mysqli_fetch_assoc($result2)){
				$supplier_id = $row['id'];
				$suppliername = $row['suppliername'];
			echo "<option value='$supplier_id'>{$suppliername}</option>";
		}
		?>
	</select></p>
	
	
	</fieldset>
	
	<div align="center"><input type="submit" name="submit" value="Insert" /></div>

</form>

<?php
if (!isset($_SESSION['user_id'])) {
	
	$url = BASE_URL . 'index.php'; // Define the URL.
	ob_end_clean(); // Delete the buffer.
	header("Location: $url");
	exit(); // Quit the script.
	
}else{
	
	echo "Welcome " . "{$_SESSION['firstname']}";
}

if ($_SERVER['REQUEST_METHOD'] == 'POST') { // Handle the form.

	// Need the database connection:
	require_once (MYSQL);
	
	// Trim all the incoming data:
	$trimmed = array_map('trim', $_POST);

	// Assume invalid values:
	$mn = $pd = $ed = $mp = $mtn = $sp = FALSE;
	
	// Check for a medicine name:
	if (preg_match ('/^[A-Z \'.-]{2,20}$/i', $trimmed['medicinename'])) {
		$mn = mysqli_real_escape_string ($dbc, $trimmed['medicinename']);
	} else {
		echo '<p class="error">Please enter a medicine name!</p>';
	}

	// Check for a production date name:
	if (!empty($trimmed['productiondate'])) {
		$pd = mysqli_real_escape_string ($dbc, $trimmed['productiondate']);
	} else {
		echo '<p class="error">Please enter a production date for this medicine!</p>';
	}
	
	// Check for a expiration date name:
	if (!empty($trimmed['expirationdate'])) {
		$ed = mysqli_real_escape_string ($dbc, $trimmed['expirationdate']);
	} else {
		echo '<p class="error">Please enter an expiration date for this medicine!</p>';
	}
	// Check for a medicine price:
	/*
	if (preg_match ('/^[A-Z \'.-]{2,40}$/i', $trimmed['medicineprise'])) {
		$mp = mysqli_real_escape_string ($dbc, $trimmed['medicineprise']);
	} else {
		echo '<p class="error">Please enter an expiration date for this medicine!</p>';
	}*/
	
	if(!empty($trimmed['medicinetypename'])){
		$mtn = $trimmed['medicinetypename'];
		} else {
			echo '<p class="error">Please select a medicinetype name for this medicine!</p>';
		}
	if(!empty($trimmed['suppliername'])){
		$sp = $trimmed['suppliername'];
		} else {
			echo '<p class="error">Please select a medicine supplier for this medicine!</p>';
		}	
		
	if ($mn && $pd && $ed && $mp && $mtn && $sp) { // If everything's OK...

			// Add the medicine to the database:
			$q = "INSERT INTO medicines 
			(medicinename, productiondate, expirationdate,medicineregistration, medicineprice, userid) 
			VALUES ('$mn','$pd', '$ed', NOW(), '$mp', '{$_SESSION['user_id']})'";
			$r = mysqli_query ($dbc, $q) or trigger_error("Query: $q\n<br />MySQL Error: " . mysqli_error($dbc));
			$medicine_id= mysqli_insert_id($dbc);
			$q2 = "INSERT INTO medicines_medicinestype 
			(medicine_id,medicinetype_id) 
			VALUES ('$medicine_id','$medicinetype_id')";
			$r2 = mysqli_query ($dbc, $q2) or trigger_error("Query: $q\n<br />MySQL Error: " . mysqli_error($dbc));
			$q3 = "INSERT INTO medicines_suppliers 
			(medicine_id,supplier_id) 
			VALUES ('$medicine_id','$supplier_id')";
			$r3 = mysqli_query ($dbc, $q3) or trigger_error("Query: $q\n<br />MySQL Error: " . mysqli_error($dbc));
			if (mysqli_affected_rows($dbc) == 1) { // If it ran OK.
				
				// Finish the page:
				echo '<h3>Thanks for adding medicines to the system!</h3>';
				include ('includes/footer.php'); // Include the HTML footer.
				exit(); // Stop the page.
				
			} else { // If it did not run OK.
				echo '<p class="error">There is no medicines saved to the system due to a technical error. 
				We apologize for any inconvenience.</p>';
			} 
			
		} else { // If one of the data tests failed.
		echo '<p class="error">Please try again.</p>';
	}

} // End of the main Submit conditional.
?>