We Keep Coding

increment value in database using PHP and AJAX

I am trying to make value +1 in database every time use use button.
my function in HTML:
function onClick(arg){
alert("thx fo click");
$.ajax({
type: 'POST',
url: 'data.php',
data: {
'arg': arg,
},
success: function(response) {
}
});
}
arg means value of button and it is a ID for a row in the database
and PHP:
<?php
$link = mysql_connect($servername, $username, $password);
$id = $_POST['arg'];
$sql = "UPDATE Buttons(SUMA) SET SUMA = SUMA + 1 WHERE ID = '$id'";
$conn->query($sql);
mysql_close($link);
?>
And that make nothing. How can i fix it?

You have several syntax errors here.
First and foremost though, check out mysqli_ (or PDO) and start using that instead of mysql_
For why to use mysqli_ - MySQL vs MySQLi when using PHP
Comparing mysqli_ and PDO - https://websitebeaver.com/php-pdo-vs-mysqli
With that out of the way....
You're defining your database connection without selecting a schema, but don't reference your schema in the query, meaning mysql won't know what to update. Either reference your schema in the connection or in each query. Also check on your table name, is it really Buttons(SUMA)?
You defined your database connection as $link, but are using $conn to attempt the query. Probably a 'typo' from copy and paste. Be careful of this...
As Artistic Phoenix mentioned, you have to make sure you're column cannot be set to NULL, and starts at 0 to begin. While you're at it and we're going through, make sure your datatype is set to int for the increment count.
After making those changes if you don't have success, I'd try running your query outside your code in a DB manager to ensure that portion is having the intended affect on your data, before looking at the errors in your code.
I'm guessing the arugment is passing correctly to your script, but to confirm, you can always echo it on the backend, and to be doubly sure alert() it in JS before it's passed through.
Take the time to go through that reading, update your script to use mysqli_ or PDO, and if you're still having troubles, I'm more than happy to jump back in here and help you further.

What is 1 + NULL it's still NULL.
IF you didn't default the column to '0' , then you can't increment it.
This can best be shown in a simple DB fiddle
Starting Null:
CREATE TABLE t(
id INT(10),
v INT(10)
);
INSERT INTO t (id)VALUES(1);
SELECT * FROM t;
UPDATE t SET v = v+1 WHERE id=1;
SELECT * FROM t;
In Both selects you will get a value of null for v as seen below in the fiddle:
https://www.db-fiddle.com/f/m1vgKpov1oiRJEfZEgmk1j/0
In simple terms, you cannot add 1 (or any number) to a NULL value. Well you can but it's still null. null + 1 = null
Starting 0:
CREATE TABLE t(
id INT(10),
v INT(10) default 0
);
INSERT INTO t (id)VALUES(1);
SELECT * FROM t;
UPDATE t SET v = v+1 WHERE id=1;
SELECT * FROM t;
In this case the first Select return 0 for v and the second returns 1 for v. As seen in the modified fiddle.
https://www.db-fiddle.com/f/m1vgKpov1oiRJEfZEgmk1j/1
Also (SQLInjection)
As I said in the comments:
What if arg = "' OR 1 --"
Or in other words don't inject user variables (or any clientside data) into your SQL or it winds up looking like this:
UPDATE `Buttons(SUMA)` SET SUMA = SUMA + 1 WHERE ID = '' OR 1 --'"
Which will increment every row in your DB that is not null. Basically the ' closes the other quote, then OR 1 is always true(for every row). Unfortinalty I cant show the -- comment part in the fiddle (it comments out the second select), but here is the end result.
https://www.db-fiddle.com/f/m1vgKpov1oiRJEfZEgmk1j/3
This is why we use prepared statements. This example is somewhat trivial but I have seen login code on here I was able to bypass simple by putting "' OR 1 LIMIT 1 --'" in, and with offset you could iterate though each user. They were looking for 1 row to be returned on the match of a username and password.
A few other things:
Table name Buttons(SUMA) is that really the name, as it will only work if escaped with the backtic. As I did in the above SQLInjection example.
$link = mysql_connect($servername, $username, $password); are these defined, the open tag is right above them. I generally chock that up to simplified example code. But it's worth asking. Obviously you can't connect to the DB if those are undefined.
Cheers!

Best algorithm to process hash data

Question is about best way to handle data.
Let's assume we have such key -> value data:
"user#gmail.com": { "name": "John",
"age": 20,
"job": "developer",
"favourite_food": ['taco', 'steak']
//...etc
}
//...etc
There is a lot of data for users with key "email", like a million.
And usually I had to search users by their email.
But today my boss came up to me and said he want to search users by their names and of course keep possibility to search by email. On the other day he said he want my program to realize search by age and so on.
My first thought was to iterate over data with, for example, this php code:
foreach($email as $data){
foreach($data as $k => $v){
if($v == 'search value'){
return $email;
}
}
}
But this solution is not good for big amount of data.
My second idea was to iterate over first data and create for each email own table to make it look like this:
$a = "user#gmail.com": {//all data}
$b = "John" : {//all data including email}
$c = "developer":{//all other data}
// and so on
But my users getting older with time, so I have to update user age every time the data in my main object changes.
So, my question is, what is the best way to implement such logic using any programming language?
Some notes:
It had to be done by using programming language without touching MySQL or any other DB.

I think using the year of birth of users instead of age might be better in this situation.
You can use index if you are using database.
If not, I think you can create index by yourself.
A simple index strategy is:
Do not change the original data, but add index dicts where the keys are index and values are email.
Like in python you can add two indices, name and yearofbirth:
name = {"John": ["xx#xx.com", "cc#cc.com", "aa#c.com"],
"Mike": ["aa#aa.com", ...],
#...etc}
yearofbirth = {"1981":["xx#xx.com", "cc#cc.com"],
#...etc}
In this way, you can search by name or yearofbirth to get the email and then fetch the original data.
And it is fast.

Check MySQL if data already exists, if not, INSERT. [PHP+jQuery Ajax]

I'm having trouble creating php code that would insert values into MySQL database but only if they don't already exist.
I send array from javascript to PHP file using $.ajax type POST.
Do I need additional 'SELECT' query to check if values already exist?
PHP File(Works, inserts values):
<?php
SESSION_START();
include('config.php');
if(isset($_POST['predictedMatches'])&&$_SESSION['userid']){
$predictedMatches=$_POST['predictedMatches'];
$userid=$_SESSION['userid'];
}else die("ERROR");
$sql="";
foreach($predictedMatches as $predictedMatch){
$sql.="INSERT INTO predictions(result,userFK,matchFK,tournamentFK) VALUES('".$predictedMatch['result']."','".$userid."','".$predictedMatch['id']."','".$predictedMatch['tourid']."');";
}
if($conn->multi_query($sql) === TRUE){
echo "OK";
}else{
echo "Error: " . $sql . "<br>" . $conn->error;
}
$conn->close();
?>

Use the ON DUPLICATE KEY UPDATE feature. It won't insert, if the primary key exists. But you have to update some value, so use the column which is in no index or in the least indexes () in your case probably result). Your primary key has to be composted out of the three FKs:
ALTER TABLE `predictions` ADD PRIMARY KEY( `userFK`, `matchFK`, `tournamentFK`);
PHP-Code, just the SQL statment (I'm a Java Guy, so i tried my best)
$sql.="INSERT INTO predictions (result, userFK, matchFK, tournamentFK) "
."VALUES('".$predictedMatch['result'] ."','".$userid."','"
.$predictedMatch['id']."','".$predictedMatch['tourid']."') "
."ON DUPLICATE KEY UPDATE result = result ;";
To know if the query was inserted you have to look at the affected row count:
1 Row - Insert
2 Rows - Update
Take a look at $conn->affected_rows after the query.
Performance
INSERT ... ON DUPLICATE KEY UPDATE is definitively faster than a SELECT and INSERT but it's slower than an INSERT of just the needed datasets. The update is done in the database, even if it is the same value. Unfortunately there is no ON DUPLICATE KEY UPDATE INGNORE. If you have a lot of inserts, that will result in updates, than it may be better to use a cache, lookup values in an array and compare with the array before inserting. Only use the ON DUPLICATE KEY UPDATE as fallback.

Passing Mysql data to PHP array then to javascript

Let me start by explaining the situation:
I have a MySql table that contains several columns, of which a user id, a race id, a lap time, a lap number and I want to put this information into an array in PHP which I will then send to a java script.
My JavaScript array should end up looking like this :
first row:
[laptime1 user1, laptime2 user1, laptime3 user1,...]
second row:
[laptime1 user2, laptime2 user2, laptime3 user2,...]
Here's my current situation:
I first tried to test this situation for a single user and ran into lots of problems because my lap times in MySql are floats and when using json_encode it turned everything into strings, which did not work for my javascript as it started outputting the wrong values.
For example:
The first value was "8" instead of "84,521", then the second value was "4", etc..)...
Sadly, I found a potential solution with the numeric check option, but cannot use it as my hosting runs a PHP version that doesn't support it.
So I found the following solution, which I fiddled with a bit and that works for a single user (it might look messy to you, I'm really a beginner and punching above my weight, but it works) :
$query = doquery("SELECT racelaptime,userid FROM {{table}} WHERE raceid='1' ORDER BY racelap", "liverace");
while(($result = mysql_fetch_array($query))) {
$data[] = (float)$result['racelaptime'];
}
$script = $script . "\nvar myArray = new Array(";
foreach ($data as $key => $value){
if ($key < (count($data)-1)){
$script = $script . $value . ',';
}
else {
$script = $script . $value . ");\n";
}
}
This outputs an array in JavaScript that looks like this :
myArray=[84.521,83.800,81.900]
Which is great, as this is exactly what my java script requires as input (time in seconds, separated by commas for each lap).
Now I would like to implement the multiple user element but I'm stumped as to how I can work that out...
My MySQL query is still sorted by race lap but I also kind of need to sort the data by user id as I want all the laps of each user sorted in 1 row, Also, the user id is unknown to me and can vary (depends which user posts the time) so I can't really do a "if userid==1 save this here and then go to next one".
Should I use a foreach statement in the while loop that stores the data, but how can I tell him to store all the laps by the same user in the first row (and the next user in the second row, etc...) without using tons of SQL queries ?
If you can offer a more elegant solution than my current one for passing the PHP array to JavaScript, I would be more than happy to make changes but otherwise a simple solution using the current "setup" would be great too (hope it's all clear enough).
Any help would be very much appreciated, thanks in advance !

For multiple user element I would use a multidimensional array >
$query = doquery("SELECT racelaptime,userid FROM {{table}} WHERE raceid='1' ORDER BY racelap", "liverace");
// Loop the DB result
while(($result = mysql_fetch_array($query))) {
// Check if this ID is already in the data array
if(!array_key_exists($result['userid'], $data)){
// Create array for current user
$data[$result['userid']] = array();
}
// Add the current race time to the array (do not need to use the float)
$data[$result['userid']][] = $result['racelaptime'];
}
// Echo json data
echo json_encode($data);
Now what you need to do on the Javascript side when handling this array is to go through each of the user
$.each(data, function(key, value){
// Use parseFloat to keep the decimal value
alert(key + ' Has the following values - ' + value);
// If you want to display the racing values you simply
$.each(value, function(k, parseFloat(v)){
alert(v);
})
})
Is this what you needed or am I completely out of the scope?

How to dynamically update drop-down list options with values in a server-generated array

I have a web form with two drop-down boxes, and I'm looking for a way to dynamically update the options of the second box based on selections from the first.
The first box represents a data type, and the second box is a list of databases associated with the selected type.
I have the basic code running smoothly here:
var TypeA_DbSuffixList = ['Test1', 'Test2', 'Test3'];
var TypeB_DbSuffixList = ['TestA', 'TestB', 'TestC'];
function fill_dbSuffixList(){
document.getElementById("dbSuffixList").options.length = 0;
var suffixMenu = document.getElementById("dbSuffixList");
var dataFormat = document.getElementById("dataFormatType");
var suffixList = dataFormat.value + "dbSuffixList";
if (suffixList == 'TypeA_dbSuffixList') {
for(index in TypeA_dbSuffixList) {
suffixMenu.options[suffixMenu.options.length] = new Option(TypeA_dbSuffixList[index], index);
}
}
if (suffixList == 'TypeB_dbSuffixList') {
for(index in TypeB_dbSuffixList) {
suffixMenu.options[suffixMenu.options.length] = new Option(TypeB_dbSuffixList[index], index);
}
}
}
That code (activated whenever a selection is made in the dataType box) clears the existing list of options and repopulates the list based on the selected value of the "dataFormatType" box.
The problem that I face is that the actual lists of database tables are not hard coded and are instead generated with the following calls to the server to avoid repetitive editing of the page every time a new database is added:
var TypeA_dbSuffixList = ${TypeA_dbSuffixList};
var TypeB_dbSuffixList = ${TypeB_dbSuffixList};
These calls return the following code:
var TypeA_dbSuffixList = [Test1, Test2, Test3];
var TypeB_dbSuffixList = [TestA, TestB, TestC];
With the above code, the initial function treats each entry in the type arrays as an undefined variable, and nothing is ever written to the drop-down list.
If I were to add
var Test1 = "Apple";
var Test2 = "Orange";
var Test3 = "Grape";
prior to the "for" loop for TypeA, then selecting TypeA from the dataType drop-down list returns "Apple", "Orange", and "Grape" as the available databases for TypeA.
Visually, I see what needs to be changed. The [Test1, Test2, Test3] returns need to be ['Test1', 'Test2', 'Test3']. I'm just unsure exactly how to go about changing it, and have exhausted every web search I can think of.
Is there a way to either change the format of the returned arrays, or use the existing format and pass variable names as drop-down selections instead of using variable values?
Any help is greatly appreciated. I will continue to search for an answer on my own as well and will post it here should I find one.

I think the cleanest solution would be to change the code on the server-side to generate a proper JavaScript array of Strings, with the values enclosed in single or double quotes.
If that's not possible for some reason, and you want a pure-JavaScript solution, then I suggest you wrap the entire JSP/ASP/PHP variable (not sure what framework you're using) in double quotes, strip the string of brackets and spaces using a regex, and then split it into a string array using the comma as a delimiter.
So in your JavaScript, this:
var TypeA_dbSuffixList = ${TypeA_dbSuffixList};
would become this:
var TypeA_dbSuffixList = "${TypeA_dbSuffixList}".replace(/[\[\]\s]/g,"").split(",");

I think the best way to convert data in a server side language into something to be used in JavaScript is to JSON encode your objects.
I'm not sure what language your using on the server, but in PHP you can do the following
var arr = <?php echo json_encode( array ('abc', 'def', 'ghi') ); ?> ;
And your output will be
var arr = ['abc', 'def', 'ghi'] ;
This will make sure that strings with embedded new lines, tabs, quotes are properly escaped.
JSP
You said you're using JSP but the code you have looks more like velocity or free marker inside JSP. In JSP you could use the following, provided you download Gson
var TypeA_dbSuffixList = <%= new Gson().toJson(TypeA_dbSuffixList) %>;