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Why was database not updating?

kingnutter

By kingnutter
in MySQL Help

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kingnutter Member

kingnutter

Posted
Posted

I had a problem solved recently on the PHP boards.

 

The code below was not updating the database. Once I had added:

 

$wid=$_POST["wid"];

 

in the "// set up error list array" it worked fine.

 

Can anyone explain why this was necessary, as the string wid is a numeric unique identifier which I wouldn't have thought needed validating or updating.

 

Many thanks,

Gary

 

<html>

<head></head>

<body>

<!-- standard page header begins -->
<p> <p>

<table width="100%" cellspacing="0" cellpadding="5"> <tr>
    <td></td>
</tr>
<tr>
    <td bgcolor="Navy"<font color="White">
    <b><font size="4">
MEDIA THESAURUS</tr>
<td bgcolor="Green"<font color="White">
    <b><font size="4">
ADMIN EDIT
</b></font>
    </td>
</tr>
</table>
<!--Standard page header ends -->

<?php

// includes

include('conf.php');

include('functions.php');

// form not yet submitted

// display initial form with values pre-filled

if (!$_POST['submit'])

{

// check for record ID

if ((!isset($_GET['wid']) || trim($_GET['wid']) == ''))

{

die('Missing record ID!');

}

// open database connection

$connection = mysql_connect($host, $user, $pass) or die ('Unable to connect!');

// select database

mysql_select_db($db) or die ('Unable to select database!');

// generate and execute query

$wid = $_GET['wid'];

$query = "SELECT word, category, tags, def, pub, author, submitted, amended, flagged FROM words WHERE wid = $wid";

$result = mysql_query($query) or die ("Error in query: $query. " . 
mysql_error());

// if a result is returned

if (mysql_num_rows($result) > 0)

{

// turn it into an object

$row = mysql_fetch_object($result);

// print form with values pre-filled

?>

<table cellspacing="5" cellpadding="5">

<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST">

<input type="hidden" name="wid" value="<?php echo $wid; ?>">

<tr>

<td valign="top"><b><font size="-1">Main Entry</font></b></td>

<td>

<input size="50" maxlength="50" type="text" name="word"

value="<?php echo $row->word; ?>">

</td>

</tr>

<tr>

<td valign="top"><b><font size="-1">Definition</font></b></td>

<td>

<input size="50" maxlength="500" type="text" name="def"

value="<?php echo $row->def; ?>">

</td>

</tr>

<tr>

<td valign="top"><font size="-1">Tags</font></td>

<td>

<input size="50" maxlength="200" type="text" name="tags"

value="<?php echo $row->tags; ?>">

</td>

</tr>

<tr>

<td colspan=2>

<input type="Submit" name="submit" value="Update">

</td>

</tr>

</form>

</table>

<?php

}

// no result returned

// print graceful error message

else

{

echo '<font size=-1>That definition could not be located in our database.</font>';

}

}

else

{

// set up error list array

$errorList = array();

$word = $_POST['word'];

$def = $_POST['def'];

$tags = $_POST['tags'];


// check for record ID

if ((!isset($_POST['wid']) || trim($_POST['wid']) == ''))

{

die ('Missing record ID!');

}

// validate text input fields

if (trim($_POST['word']) == '')

{

$errorList[] = 'Invalid entry: Word';

}

if (trim($_POST['def']) == '')

{

$errorList[] = "Invalid entry: Definition";

}

if (trim($_POST['tags']) == '')

{

$errorList[] = "Invalid entry: Tags";

}

// check for errors

// if none found...

if (sizeof($errorList) == 0)

{

// open database connection

$connection = mysql_connect($host, $user, $pass) or die ('Unable to connect!');

// select database

mysql_select_db($db) or die ('Unable to select database!');

// generate and execute query

$query = ("UPDATE words SET word = '$word', def = '$def', tags = '$tags', WHERE wid = '$wid'");

$result = mysql_query($query) or die ("Error in query: $query. " . 
mysql_error());

// print result

echo '<font size=-1>Update successful.';

echo '<a href=record.php>Go back to the main menu</a>.</font>';

// close database connection

mysql_close($connection);

}

else

{

// errors occurred

// print as list

echo '<font size=-1>The following errors were encountered:';

echo '<br>';

echo '<ul>';

for ($x=0; $x<sizeof($errorList); $x++)

{

echo "<li>$errorList[$x]";

}

echo '</ul></font>';

}

}

?>

<!-- standard page footer -->

</body>

</html>

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https://forums.phpfreaks.com/topic/99672-why-was-database-not-updating/
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zenag Newbie

zenag

Posted
Posted

hi...again...

ur posting the selected value to be updated  from the form below, u can also update via ..

"UPDATE words SET word = '$word', def = '$def', tags = '$tags', WHERE word = '$word', "

but its not a correct way...since  $wid is the unique identifier for the selected values in the form..

its the unique id which shows database which row has to  be updated....

 

<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST">

 

<input type="hidden" name="wid" value="<?php echo $wid; ?>">

 

<tr>

 

<td valign="top"><b><font size="-1">Main Entry</font></b></td>

 

<td>

 

<input size="50" maxlength="50" type="text" name="word"

 

value="<?php echo $row->word; ?>">

 

</td>

 

</tr>

 

<tr>

 

<td valign="top"><b><font size="-1">Definition</font></b></td>

 

<td>

 

<input size="50" maxlength="500" type="text" name="def"

 

value="<?php echo $row->def; ?>">

 

</td>

 

</tr>

 

<tr>

 

<td valign="top"><font size="-1">Tags</font></td>

 

<td>

 

<input size="50" maxlength="200" type="text" name="tags"

 

value="<?php echo $row->tags; ?>">

 

</td>

 

</tr>

 

<tr>

 

<td colspan=2>

 

<input type="Submit" name="submit" value="Update">

 

</td>

 

</tr>

 

</form>

 

kingnutter Member

kingnutter

Posted
  • Author
Posted

Thanks for that.

 

So is it prerequisite that all the fields in the form (even hidden ones) are set up in the error list array? $wid will not be changed so I am confused as to why it needs error-checking.

 

since some database table can have many identical fields  ...except the unique identifier id...

so its a necessary.... to update  tables using unique identifier...

 

Exactly what I was doing. UPDATE variable WHERE record = unique identifier. However, below you say it is incorrect:

 

ur posting the selected value to be updated  from the form below, u can also update via ..

"UPDATE words SET word = '$word', def = '$def', tags = '$tags', WHERE word = '$wid', "

but its not a correct way...since  $wid is the unique identifier for the selected values in the form..

its the unique id which shows database which row has to  be updated...

 

I was doing both. Please someone show me what the correct way is (even though this is working)

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