Update value only if Null php/mysql - php

Thanks for checking out my question. I am trying to only update a value in my database if that field is null (so existing users won't be overwritten if someone tries to signup for a spot that is all ready taken and an error message will be output). I have listed below 2 of the most recent scripts I have tried. The first script works for updating the database if the select statement is not there but will overwrite users if entered for the same day and time. Thanks everybody!
$sql = ("SELECT `player1` FROM `users` where id = '$id' and Times = '$time'");
$result = $conn->query($sql);
if ($result->fetch_assoc === NULL) {
$update_player = ("UPDATE users SET player1 = '$name' where id = '$id' AND Times = '$time'")
if($update_player){
echo "Date for $name inserted successfully!";
}
}
else {
echo 'That spot is all ready taken!';
}
//2nd script
$query=mysql_query("UPDATE users SET
player1 = isNULL (player1, $name)
where id = '$id' AND Times = '$time'" );
if($query){
echo "Data for $name inserted successfully!";
}
else {
echo 'That spot is all ready taken!';
}

The following code should do the trick:
$query=mysql_query("UPDATE users SET
player1='$name'
where id = '$id' AND Times = '$time' AND player1 IS NULL" );
if(mysql_affected_rows() == 1){
echo "Data for $name inserted successfully!";
}
else {
echo 'That spot is all ready taken!';
}
Note that you should use pdo or mysqli functions instead.

Try This.
while($row = $result->fetch_assoc) {
if($row['player1'] == NULL){
$update_player = ("UPDATE users SET player1 = '$name' where id = '$id' AND Times = '$time'")
}

Related

Select the updated value using PHP

I'm working on attendance base on login and logout, Is there a way I can make this code work, I'm having a problem on after successfully update the data it will go to another notepad and in there it has a select query that will display the image and basic info of user. But when I tried to logout it displays different user info and images.
Here is my code for php:
<?php
include_once ('connection.php');
if(isset($_POST['submit']))
{
$username2 = $_POST['username2'];
$password1= $_POST['password1'];
$time=date("H:i:s");
$sql = mysqli_query($conn,"SELECT tbl_visitor.Birthday,tbl_visitor.School_Company,tbl_visitor.Contact_number,tbl_visitor.Visitor_Address,tbl_visitor.image,tbl_visitor.Visitor_username,tbl_visitor.Visitor_id,tbl_visitor.Visitor_password,concat(Visitor_first_name,'',Visitor_last_name) as name,
tbl_visitor_form.Time_in,tbl_visitor_form.Time_out , tbl_visitor_form.Number FROM tbl_visitor LEFT JOIN tbl_visitor_form on tbl_visitor.Visitor_id = tbl_visitor_form.Visitor_id WHERE tbl_visitor.Visitor_username = '$username2' and tbl_visitor.Visitor_password = '$password1'
order by Number DESC limit 1");
$count = mysqli_num_rows($sql);
if ($count == 0) {
$_SESSION['error_message'] = "Incorrect username or password";
header("Location:logout.php?");
} else{
while ($row = mysqli_fetch_array($sql)) {
$username2 = $row['Visitor_username'];
$password1 = $row['Visitor_password'];
$name=$row['name'];
$id=$row['Visitor_id'];
$image=$row['image'];
if(empty($row['Time_in'])) {
header("location:visitorvalidate1.php");
} else if(empty($row['Time_out'])){
$InsertSql = "Update tbl_visitor_form set Time_out = '$time' where Visitor_username='$username2' and Visitor_password = '$password1' order by Number DESC limit 1 ";
$res = mysqli_query($conn, $InsertSql);
header("location:outsuccess.php?");
}else{
header("location:visitorvalidate1.php");
}
}
}
}
?>
here is my outsuccess.php:
<?php
include_once('connection.php');
$sql = "select Visitor_username, image, Visitor_name from tbl_visitor_form
order by Number DESC limit 1 ";
$result = mysqli_query($conn,$sql);
while( $row = mysqli_fetch_array($result)) {
$uname=$row['Visitor_username'];
$name=$row['Visitor_name'];
$image=$row['image'];
}
?>
the first query above is working but the second query in select has the problem, it selects different value after the update. for example, there is two user has already login user1 and user2 when I try to logout user1 it successfully updated but it displays the info of user2 instead of user1 on outsuccess.php. Hope you can help me fix this. Advance Thanks

Duplicate entry '1' for key 'PRIMARY' when updating the table

I have a problem when trying to update table after checking row. Not sure if the "if" statement is wrong, however I'm not quite sure, why the UPDATE sql is returning this error. I wouldn't be suprised if INSERT did that.
Here's part of code:
$sql = "SELECT user_id FROM players WHERE user_id = '$id'";
$result = $connect->query($sql);
if($result->num_rows > 0)
{
$sql = "UPDATE players SET user_id = '$Player->user_id', display_name = '$Player->display_name', attackPower = '$Player->attackPower]', defensePower = '$Player->defensePower'";
if($connect->query($sql) === TRUE)
{
echo 'Table has been successfully updated.';
}else{
echo 'There has been a problem with updating the "players" table. <br>Error: '.$connect->error;
}
}else{
$sql = "INSERT INTO players(user_id, display_name, attackPower, defensePower) VALUES('$Player->user_id', '$Player->display_name', '$Player->attackPower', '$Player->defensePower')";
if($connect->query($sql) === TRUE)
{
echo'Table has been successfully migrated.';
}else{
echo'Table migration has failed.';
}
}
$connect->close();
INSERTing is working just fine. I would appreciate any advice. Thanks.
Your update query should look like:
$sql = "UPDATE `players` SET `display_name` = '{$Player->display_name}',
`attackPower` = '{$Player->attackPower}', `defensePower` = '{$Player->defensePower'}
WHERE `user_id` = '{$Player->user_id}'";
It cause an error because Identity columns are not updateable.
You can update every columns except them:
$sql = "UPDATE players SET display_name = '$Player->display_name', attackPower = '$Player->attackPower]', defensePower = '$Player->defensePower'";
As #aynber and #Julqas said, problem was my sql was missing WHERE condition. Thanks for help.

Create a "Secret Santa" generator using MySQL and PHP

I am trying to create a Secret Santa system using a PHP page and a MySQL database to store the details so if someone forgets their match they can re-request it.
Step 1: I created a random number generator based on the number of people in the list in the database.
Count Function:
$maxSQL = "SELECT COUNT(id) as total FROM secretsanta";
$maxRS = mysqli_query($conn, $maxSQL);
$maxQuery = mysqli_fetch_array($maxRS);
$maxpersons = $maxQuery['total'];
Then the Random Number Generator:
$assigned = rand(1,$maxpersons);
Step 2: Test if the random number matches the persons own id and regenerate a new number if true.
do {
$assigned = rand(1,$maxpersons);
} while ($assigned==$id);
Step 3: Write the paired id to the persons database record.
$assignSQL = "UPDATE secretsanta SET assigned = '".$assigned."' WHERE secretsanta.id = ".$id;
if (mysqli_query($conn, $assignSQL)) {
echo "Record updated successfully";
} else {
echo "Error updating record: " . mysqli_error($conn);
}
The Problem: Now I need to check that other people aren't assigned to that person or otherwise some could miss out and others would get more than others.
I tried to implement a function that contained a query to test each record to see if that number already existed and was hoping to add it as a condition to perhaps a while or do while statement?
if (!function_exists('checkRandom')){
function checkRandom($funcid){
$Check_SQL = "SELECT assigned FROM secretsanta ORDER BY id ASC";
$Check_RES = mysqli_query($conn, $Check_SQL);
if (Check_RES) {
while ($CheckArray = mysqli_fetch_array($Check_RES, MYSQLI_ASSOC)) {
$CheckAsgn = $CheckArray['assigned'];
if ($funcid==$CheckAsgn) {return true;}else{return false;}
}
}
}
}
Then implement it into the do while statement like this:
do {
$assigned = rand(1,$maxpersons);
} while ($assigned==$id||checkRandom($assigned));
No luck so far...HELP!.. please :)
P.S. I know there are websites that already do this, I just don't trust them to give out mine and family email address' if I can make my own private version myself.
Using your method, the first few assignments will be done with no problem, but imagine the last unassigned entry and how many times it will try a random number only to find the person with that id is already assigned..
I'm gonna give you another approach to your problem: for each user that you want to assign a santa to, make a new SELECT statement with a WHERE clause that lets you select only those users that are not assigned yet.
check out my code and see if that helps you. I just typed this and didnt test it so there could be some mistakes.
// load all unassigned users into an array
$unassignedUsers = [];
$query = "SELECT id, assigned FROM secretsanta WHERE assigned is NULL";
$res = mysqli_query($conn, $query);
while($row = mysqli_fetch_assoc($res){
$unassignedUsers[] = $row;
}
if(count($unassignedUsers) == 1){
echo 'There is only 1 unassigned user. Therefore he cannot be matched';
} else {
// for loop for each user in DB that is not assigned yet
//for ($i = 1;$i <= count($unassignedUsers); $i++){
$i = 0;
foreach($unassignedUsers as $user)
// if its the second-to-last iterations of the for-loop, check for legality of the last one
if(count($unassignedUsers) - $i == 1){
$lastUserID = $unassignedUsers[count($unassignedUsers)-1]['id'];
$query = "SELECT id FROM secretsanta WHERE assigned is NULL AND id = ".$lastUserID;
$res = mysqli_query($conn, $query);
$rowcount = mysqli_num_rows($res);
if ($rowcount){
// last user is still unassigned
$query = "UPDATE secretsanta SET assigned = '".$lastUserID."' WHERE id = ".$user['id'];
if(mysqli_query($conn, $query)){
echo "Record with id ".$user['id']." updated successfully";
} else {
echo "Error updating record: ".mysqli_error($conn);
}
}
} else {
// select all unassigned users
$unassignedIDs = [];
$query = "SELECT id FROM secretsanta WHERE assigned is NULL AND id <> ".$user['id'];
$res = mysqli_query($conn, $query);
while($row = mysqli_fetch_assoc($res){
$unassignedIDs[] = $row['id'];
}
// get a random id from $unassignedIDs
$randomIndex = rand(0, count($unassignedIDs)-1);
$randomID = $unassignedIDs[$randomIndex];
// assign $randomID to user
$query = "UPDATE secretsanta SET assigned = '".$randomID."' WHERE id = ".$user['id'];
if(mysqli_query($conn, $query)){
echo "Record with id ".$user['id']." updated successfully";
} else {
echo "Error updating record: ".mysqli_error($conn);
}
}
$i++;
}
}
last edit: refactored whole code so it is able to be run multiple times and only assigns new users who are not assigned yet.
Step 1 is dependent on have a contiguous set of ids for the people. Think what happens if '3' leaves the company and it hires 6 to replace them....1,2,4,5,6 ($maxpersons=5)
"Now I need to check" - no you are still trying to solve the problem by guessing then seeing if your guess worked. Use an algorithm which is always going to return a correct result. The method below requires the addition of a temporary field 'sequence' of type float.
mysqli_query($conn,"UPDATE secretsanta SET sequence=RAND()");
$first=false;
$prev=false;
$all=mysqli_query($conn, "SELECT * FROM secretsanta ORDER BY sequence, id");
while ($r=mysqli_fetch_assoc($all)) {
if (false===$first) {
$first=$r['id'];
} else {
save_pair($prev, $r['id']);
}
$prev=$r['id'];
}
save_pair($prev, $first);
(but with better error checking)

How to deactivate an account in PHP?

I am trying to make a deactivate account so ...When I click a link I want the account status to be updated in the database so it will turn 0. Every time I click the link here nothings happens it just re direct me to another page this my code for the deactivating
<?php
include "../includes/dbcon.php";
if(isset($_GET['user_id']))
{
$result = mysql_query("SELECT user_id FROM users WHERE user_id = $user_id");
while($row = mysql_fetch_array($result))
{
echo $result;
$status = $row($_GET['status']);
if($status == 1)
{
$status = 0;
$update = mysql_query("Update users set status = $status");
header("location: admin_manage_account.php");
}
else
{
echo "Already deactivated";
}
}
}
?>
I don't know what is your problem exactly, but why do you select the id based on the id?
Why don't you do something like "UPDATE users SET status = $status WHERE user_id = $user_id" in the first place?
In your example you don't even have a condition in the update statement...
If you want to "toggle/flip" a value you can just do something like:
UPDATE users SET status = NOT status WHERE user_id = $user_id
This way, true become false, false become true, etc.
You code is not ok on many reasons. But the most serious problem is SQL Injection attack!
If attacker put non-expected value to your user_id param, your sql like that "SELECT user_id FROM users WHERE user_id = $user_id" and that "Update users set status = $status WHEREuser_id= '$user_id'" can cause very serious problems.
For example: user_id can be: "0; DROP TABLE users"
Be careful with your code, rewrite it
Too many things needed to be improved. You should not use MySQL either. Consider MySQLi or PDO. BTW here is an updated version of your own code which should work:
<?php
include "../includes/dbcon.php";
if(isset($_GET['user_id']))
{
$user_id = $_GET['user_id']; // I assume you want to capture it from URL
$result = mysql_query("SELECT user_id FROM users WHERE user_id = $user_id");
while($row = mysql_fetch_array($result))
{
// echo $result; why do you echo it? No need
/* $status = $row($_GET['status']); should be: */
$status = $row['status'];
if($status == 1)
{
$status = 0;
$update = mysql_query("Update users set status = $status WHERE `user_id` = '$user_id'");
header("location: admin_manage_account.php");
}
else
{
echo "Already deactivated";
}
}
}
?>
Previously, you were not defining $user_id. Moreover, it wasn't correct the way you were getting the status ($status) of the user.

Is this coding wrong it's not working properly

The below script inputs data to a database this takes some information from a form then stores them in to the database. And I'm also using uplodify to upload a image file and store the file name in the database but my issue is this data processing script keeps updating the row ID one never jumps to the second line I tried every thing can some one help me with this or show me what I'm doing wrong.
Also this checks the ID and if it's not equal to 1 then does an insertion if it's equal then update it but this not happening.
The ID is auto incrementing.
My script
<?php
/**
* #author SiNUX
* #copyright 2013
*/
include ('connect.php');
$getId = mysql_query("SELECT ID FROM poiinfo ORDER BY ID DESC LIMIT 1");
$row = mysql_fetch_array($getId);
$poiName = $_REQUEST['Name'];
$poiDes = $_REQUEST['Descrip'];
$poiCon = $_REQUEST['ConInfo'];
//$poiId = $_REQUEST['pID'];
if($row['ID'] != "1"){
$dbData = "INSERT INTO poiinfo(`Name`, `Des.`, `Contact`) VALUES ('$poiName','$poiDes','$poiCon')";
$putData = mysql_query($dbData);
if ($putData){
echo "Data inserted";
}else {
echo "Not Done";
}
}else {
$updLn = "UPDATE `poiinfo` SET `Name`='$poiName',`Des.`='$poiDes',`Contact`='$poiCon'";
$updDone = mysql_query($updLn);
if ($updDone){
echo "Data inserted";
}else {
echo "Not Done";
}
}
?>
I tried u r suggestions but it's still the same now my code for the update is looks like this.
$updLn = "UPDATE `poiinfo` SET `Name`='$poiName',`Des.`='$poiDes',`Contact`='$poiCon' WHERE `ID`='".$row['ID']."'";
But still it keeps up dating the ID 1 not moving on to the next one.
Your update query is missing a WHERE clause. Try this:
$updLn = "UPDATE `poiinfo` SET `Name`='$poiName',`Des.`='$poiDes',`Contact`='$poiCon' WHERE ID = '".$row['ID']."'";
Also be beware of MySQL Injections: http://en.wikipedia.org/wiki/SQL_injection
To check why your update failed, you should call mysql_error in your last else clause :
} else {
echo mysql_error();
}
As for the first problem : if you never insert a new record (I don't see how that could happen, provided your code), you will never have a record whose ID is 2.
$updLn = "UPDATE `poiinfo` SET `Name`='$poiName',`Des.`='$poiDes',`Contact`='$poiCon'";
You need a where clause in this sql to specify a record to update. Currently it is updating all records.
$updLn = "UPDATE `poiinfo` SET `Name`='$poiName',`Des.`='$poiDes',`Contact`='$poiCon' WHERE `ID` = ".$row['id']";";
You will need to set an $id variable for this to work.

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