PHP
By Web Monkey
Page 5 — Make the Forms Smarter
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Throughout this tutorial, I've been loading the SQL statement
into a variable ($sql) before firing the query at the database
with mysql_query(). This is useful for debugging. If something
goes wrong, you can always echo the SQL to the screen to examine
it for mistakes.
We already know how to get data into the database. Now let's
try modifying records that are already in the database. Editing
data combines two elements we've already seen: displaying
data on the screen and sending data back to the database via
form input. However, editing is slightly different in that
we have to show the appropriate data in the form.
First, let's recycle the code from Lesson 1 to display the
employee names on our page. But this time through, we're going
to populate our form with employee information. It should
look a little like this:
<html>
<body>
<?php
$db
= mysql_connect("localhost", "root");
mysql_select_db("mydb",$db);
if
($id) {
//
query the DB
$sql
= "SELECT * FROM employees WHERE id=$id";
$result
= mysql_query($sql);
$myrow
= mysql_fetch_array($result);
?>
<form
method="post" action="<?php echo $PHP_SELF?>">
<input
type=hidden name="id" value="<?php echo
$myrow["id"] ?>">
First
name:<input type="Text" name="first"
value="<?php echo $myrow["first"] ?>"><br>
Last
name:<input type="Text" name="last"
value="<?php echo $myrow["last"] ?>"><br>
Address:<input
type="Text" name="address" value="<?php
echo $myrow["address"] ?>"><br>
Position:<input
type="Text" name="position" value="<?php
echo $myrow["position"] ?>"><br>
<input
type="Submit" name="submit" value="Enter
information">
</form>
<?php
} else
{
//
display list of employees
$result
= mysql_query("SELECT * FROM employees",$db);
while
($myrow = mysql_fetch_array($result)) {
printf("<a
href=\"%s?id=%s\">%s %s</a><br>\n",
$PHP_SELF, $myrow["id"], $myrow["first"],
$myrow["last"]);
}
}
?>
</body>
</html>
We just echoed the field information into the value attribute
of the each element, which was fairly easy. Let's build on
this a little more. We will add the ability to send the edited
code back to the database. Again, we're going to use the Submit
button to test whether we need to process the form input.
Also note the slightly different SQL statement we use.
<html>
<body>
<?php
$db
= mysql_connect("localhost", "root");
mysql_select_db("mydb",$db);
if
($id) {
if
($submit) {
$sql
= "UPDATE employees SET first='$first',last='$last',address='$address',position='$position'
WHERE id=$id";
$result
= mysql_query($sql);
echo
"Thank you! Information updated.\n";
}
else {
//
query the DB
$sql
= "SELECT * FROM employees WHERE id=$id";
$result
= mysql_query($sql);
$myrow
= mysql_fetch_array($result);
?>
<form
method="post" action="<?php echo $PHP_SELF?>">
<input
type=hidden name="id" value="<?php echo
$myrow["id"] ?>">
First
name:<input type="Text" name="first"
value="<?php echo $myrow["first"] ?>"><br>
Last
name:<input type="Text" name="last"
value="<?php echo $myrow["last"] ?>"><br>
Address:<input
type="Text" name="address" value="<?php
echo $myrow["address"] ?>"><br>
Position:<input
type="Text" name="position" value="<?php
echo $myrow["position"] ?>"><br>
<input
type="Submit" name="submit" value="Enter
information">
</form>
<?php
}
} else
{
//
display list of employees
$result
= mysql_query("SELECT * FROM employees",$db);
while
($myrow = mysql_fetch_array($result)) {
printf("<a
href=\"%s?id=%s\">%s %s</a><br>\n",
$PHP_SELF, $myrow["id"], $myrow["first"],
$myrow["last"]);
}
}
?>
</body>
</html>
And that's that. We've managed to combine most of the features
we've seen into one script. You can also see how we've used
an if() statement inside another if() statement to check for
multiple conditions.
It's time to put it all together and make one killer script.
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