I'm a little confused about breaking out and continuing out of loops etc. I have 2 SQL queries that match user priveleges against the user's actual priveleges with the new ones put it. However, if some of the new priveleges match the one the user has, I want to skip the SQL insert and move on to the next one:
public static function insertPriveleges($user_id,$priveleges)
{
$ex = explode(",",$priveleges); // separated by commas
if(count($ex)>0)
{
$x = false;
foreach($ex as $i => $priv)
{
$check_user = mysql_query("SELECT * FROM users_access_codes WHERE user_id='$user_id'") or die(mysql_error()); // get user's current priveleges
while($check_data = mysql_fetch_array($check_user))
{
if($check_data['access_code']!=$priv)
{
//if it doesn't match, insert
$sql = "INSERT INTO users_access_codes (uaID,user_id,access_code) VALUES (NULL,'".$user_id."','$priv')";
}
}
}
}
}
I almost never have a situation that needs to match more than two things in loops. I need to make sure I don't end up with double priveleges for that user. I know there must be a 'continue' statement somewhere in the inner loop, but not sure where.
After your INSERT statement, you can add continue 2 to bring you back to the top of your foreach ($ex as .... You can also use break; in this case because there's nothing after your inner while.
However, you don't actually need it if you do it differently. Instead of reading the table for each privilege, just read all of them once and them compare.
This code will get all privileges from the database and then only inserts those that are missing, based on $ex; it uses array_diff() to calculate the difference between the two.
public static function insertPriveleges($user_id, $priveleges)
{
$ex = explode(",", $priveleges); // separated by commas
if (count($ex) > 0) {
// get user's current priveleges
$check_user = mysql_query("SELECT * FROM users_access_codes
WHERE user_id='$user_id'") or die(mysql_error());
$actual = array();
while ($row = mysql_fetch_array($check_user)) {
$actual[] = $row['access_code'];
}
foreach (array_diff($ex, $actual) as $priv) {
//if it doesn't match, insert
$sql = "INSERT INTO users_access_codes (uaID,user_id,access_code) VALUES (NULL,'".$user_id."','$priv')";
mysql_query($sql);
}
}
}
Btw, you could consider using INSERT IGNORE INTO because of race conditions, but because you're not checking the statement return value, it won't matter here :)
Simply add a break after the INSERT:
public static function insertPriveleges($user_id,$priveleges)
{
$ex = explode(",",$priveleges); // separated by commas
if(count($ex)>0)
{
$x = false;
foreach($ex as $i => $priv)
{
$check_user = mysql_query("SELECT * FROM users_access_codes WHERE user_id='$user_id'") or die(mysql_error()); // get user's current priveleges
while($check_data = mysql_fetch_array($check_user))
{
if($check_data['access_code']!=$priv)
{
//if it doesn't match, insert
$sql = "INSERT INTO users_access_codes (uaID,user_id,access_code) VALUES (NULL,'".$user_id."','$priv')";
break;
}
}
}
}
}
To be complete I would recommand the reading of the following link:
http://php.net/manual/en/faq.databases.php#faq.databases.mysql.deprecated
Related
I have strings of usernames in array . I want to generate a unique string of username which do not exits in array.(probably with some numbers following the username)
How do I achieve this?
I have summarize the code:
function generate_unique_username(){
$firstname = "james";//data coming from user
$lastname = "oduro";//data coming from user
$new_username = $firstname.$lastname;
$usersnames = array("james39","oduro32","kwame93","elvisasante","frimpong32","edward32","jamesoduro");
//Loop through ARRAY usernames and check elements against VAR $new_username
if (in_array($new_username, $usersnames)) {
//generate new username which is not inside array
//the new generated string should also be check against array to ensure is doens not exit.
}else{
return $new_username;
}
}
Thank you.
Generating username from the stored array is not a good practice, I would suggest you to use the database.
If you are using the database instead of the array, you can use the best method to generate the unique username as following:
function generate_unique_username(){
$firstname = "james";//data coming from user
$lastname = "oduro";//data coming from user
$new_username = $firstname.$lastname;
/* Note: writing here pseudo sql code, replace with the actual php mysql query syntax */
$query = "SELECT COUNT(id) as user_count FROM user WHERE username like '%".$new_username."%'";
$result = mysql_query($query);
$count = $result['user_count'];
if(!empty($count)) {
$new_username = $new_username . $count;
}
return $new_username;
}
I think in this case you should first off try and assign cooler user names to the users then when that fails you go for a number suffix. This is an approach I may use. You may need to change the code to your more preferred and secured mysqli call like using the PDO or MySQLI prepared statement.
//function that will be used to figure out if the user name is available or not
function isAvailable($userName){
global $mysqli;
$result = $mysqli->query("SELECT id FROM users WHERE user_name='$userName'") or die($mysqli->error());
// We know username exists if the rows returned are more than 0
if ( $result->num_rows > 0 ) {
//echo 'User with this username already exists!';
return false;
}else{
return true;
}
}
function generate_unique_username($firstname, $lastname, $id){
$userNamesList = array();
$firstChar = str_split($firstname, 1)[0];
$firstTwoChar = str_split($firstname, 2)[0];
/**
* an array of numbers that may be used as suffix for the user names index 0 would be the year
* and index 1, 2 and 3 would be month, day and hour respectively.
*/
$numSufix = explode('-', date('Y-m-d-H'));
// create an array of nice possible user names from the first name and last name
array_push($userNamesList,
$firstname, //james
$lastname, // oduro
$firstname.$lastname, //jamesoduro
$firstname.'.'.$lastname, //james.oduro
$firstname.'-'.$lastname, //james-oduro
$firstChar.$lastname, //joduro
$firstTwoChar.$lastname, //jaoduro,
$firstname.$numSufix[0], //james2019
$firstname.$numSufix[1], //james12 i.e the month of reg
$firstname.$numSufix[2], //james28 i.e the day of reg
$firstname.$numSufix[3] //james13 i.e the hour of day of reg
);
$isAvailable = false; //initialize available with false
$index = 0;
$maxIndex = count($userNamesList) - 1;
// loop through all the userNameList and find the one that is available
do {
$availableUserName = $userNamesList[$index];
$isAvailable = isAvailable($availableUserName);
$limit = $index >= $maxIndex;
$index += 1;
if($limit){
break;
}
} while (!$isAvailable );
// if all of them is not available concatenate the first name with the user unique id from the database
// Since no two rows can have the same id. this will sure give a unique username
if(!$isAvailable){
return $firstname.$userId;
}
return $availableUserName;
}
//Get the unique user id from your database, for now let's go with 30
$userId = 30;
echo generate_unique_username('john', 'oduro', $userId);
Also, it would be nice to provide a fallback feature where the user can change their user name to any other unique value, in case they do not like the auto-generated value.
I have an application that is passing a list of system printers to a PHP application. I am trying to set it up to ignore the printers that are basically just "software" printers. As you can see from the code below(which is by no means pretty). That I have an outer(parent) foreach that is looping through the printer list that is provided in a string that is delimited by a "pipe" symbol. Inside of that I have a second(child) foreach, that loops through a list of words that are common in the software printers names (i.e.. Adobe PDF would match the word "PDF")
So my question is this, the parent loop works fine, the printers are inserted in the database from the string, however none of my attempts at filtering out the ones that match the keywords have been excluded. So How would you suggest going about breaking out of the "child" foreach to tell the parent to skip that loop?
<?php
// Set all QUEUE Printers to Unavailable, so we can reset as active only those that are present
$SQL = "UPDATE `queues_printers` SET `status`='0' WHERE (`queue_id`='".$_GET['queue']."')";
$result = $mysqli->query($SQL);
// Process Printers
$ignore_names = array("PDF","OneNote","Fax","Microsoft XPS Document Writer","RemotePrinter");
$ignoreit=false;
$today = date("Y-m-d");
// Get list from $_GET[printers]
$printers = explode("|",base64_decode($_GET['printers']));
// Add/Update them
foreach ($printers as $printer){
// Check if this printer is to be ignored(i.e.. pdf printers, fax software, and other software printers are not useful)
foreach ($ignore_names as $ignored) {
if($ignoreit === false){
if (strpos($printer,$ignored) === true) {
$ignoreit = true;
break;
}
}
}
if($ignoreit === true){
$ignoreit = false;
continue;
}
// See if this is an existing printer and update it to available
$SQL = "SELECT DISTINCT id FROM queues_printers WHERE queue_id = '".$_GET['queue']."' AND name = '".$printer."'";
$result = $mysqli->query($SQL);
$row_cnt = $result->num_rows;
if ($row_cnt > '0'){
$printer_detail = $result->fetch_array(MYSQLI_ASSOC);
$UpdateSQL = "UPDATE `queues_printers` SET `status`='1', `last_seen`='".$today."' WHERE (`id`='".$printer_detail["id"]."')";
$result2 = $mysqli->query($UpdateSQL);
$result->close();
}
else{
// Otherwise add it
$InsertSQL = "INSERT INTO `queues_printers` (`queue_id`, `name`, `status`, `last_seen`) VALUES ('".$_GET['queue']."', '".$printer."', '1', '".$today."')";
$result2 = $mysqli->query($InsertSQL);
}
}
$mysqli->close();
?>
Use the break statement.
An example
foreach(array(1,1,1,1) as $k) {
if (!$k) {
break;
}
}
It can also have a int value that determines how many nested loops it can break out of,
break 2; // will break out two nested loops
To answer your question in more detail wouldn't it be better to just check if they aren't to be ignored and then continue instead of the other way around.
foreach($printers as $printer) {
// Do default stuff to all printers
if (!strpos($printer,$ignored)) {
// Do stuff with unignored printers
}
}
I don't know if this is really your problem, but this line will never be true:
if (strpos($printer,$ignored) === true)
strpos() returns a false or an integer, but never a true.
Furthermore: using break; without a parameter is like using break 1;, meaning it will only break out of the inner most child loop. This is already what you want.
I am trying to make a script to check if an int is already added to my database. If so, it will re-generate another random number and check again. If it doesn't exist, it'll insert into the database.
However, I am having troubles. If a number exists, it just prints out num exists, how would I re-loop it to check for another and then insert that? I have tried to use continue;, return true; and so on... Anyway, here is my code; hopefully someone can help me!
<?php
require_once("./inc/config.php");
$mynum = 1; // Note I am purposely setting this to one, so it will always turn true so the do {} while will be initiated.
echo "attempts: ---- ";
$check = $db->query("SELECT * FROM test WHERE num = $mynum")or die($db->error);
if($check->num_rows >= 1) {
do {
$newnum = rand(1, 5);
$newcheck = $db->query("SELECT * FROM test WHERE num = $newnum")or die($db->error);
if($newcheck->num_rows >= 1) {
echo $newnum . " exists! \n";
} else {
$db->query("INSERT test (num) VALUES ('$newnum')")or die($db->error);
echo "$newnum - CAN INSERT#!#!#";
break;
}
} while(0);
}
?>
I think the logic you're looking for is basically this:
do {
$i = get_random_int();
} while(int_exists($i));
insert_into_db($i);
(It often helps to come up with some functions names to simplify things and understand what's really going on.)
Now just replace the pseudo functions with your code:
do {
$i = rand(1, 5);
$newcheck = $db->query("SELECT * FROM test WHERE num = $i")or die($db->error);
if ($newcheck->num_rows >= 1) {
$int_exists = true;
} else {
$int_exists = false;
}
} while($int_exists);
$db->query("INSERT test (num) VALUES ('$i')") or die($db->error);
Of course, you can do a little more tweaking, by shortening...
// ...
if ($newcheck->num_rows >= 1) {
$int_exists = true;
} else {
$int_exists = false;
}
} while($int_exists);
...to:
// ...
$int_exists = $newcheck->num_rows >= 1;
} while($int_exists);
(The result of the >= comparison is boolean, and as you can see, you can assign this value to a variable, too, which saves you 4 lines of code.)
Also, if you want to get further ahead, try to replace your database calls with actual, meaningful functions as I did in my first example.
This way, your code will become more readable, compact and reusable. And most important of all, this way you learn more about programming.
The logic is incorrect here. Your do-while loop will get executed only once (as it's an exit-controlled loop) and will stop on the next iteration as the while(0) condition is FALSE.
Try the following instead:
while($check->num_rows >= 1) {
$newnum = rand(1, 5);
$newcheck = $db->query("SELECT * FROM test WHERE num = $newnum")or die($db->error);
if ($newcheck->num_rows >= 1) {
echo $newnum . " exists! \n";
} else {
$db->query("INSERT test (num) VALUES ('$newnum')") or die($db->error);
echo "$newnum - CAN ISNERT#!#!#";
break;
}
}
Sidenote: As it currently stands, your query is vulnerable to SQL injection and could produce unexpected results. You should always escape user inputs. Have a look at this StackOverflow thread to learn how to prevent SQL injection.
Here is an example of some code that I threw together using some of my previously made scripts. You will notice a few changes compared to your code, but the concept should work just the same. Hope it helps.
In my example I would be pulling the database HOST,USER,PASSWORD and NAME from my included config file
require_once("./inc/config.php");
echo "attempts: ---- ";
$running = true;
while($running == true) {
//create random number from 1-5
$newnum = rand(1,5);
//connect to database
$mysqli = new mysqli(HOST, USER, PASSWORD, NAME);
//define our query
$sql = "SELECT * FROM `test` WHERE `num` = '".$$newnum."'";
//run our query
$check_res = mysqli_query($mysqli, $sql) or die(mysqli_error($mysqli));
//check results, if num_rows >= our number exists
if (mysqli_num_rows($check_res) >= 1){
echo $newnum . " exists! \n";
}
else { //our number does not yet exists in database
$sql = "INSERT INTO `test`(`num`) VALUES ('".$newnum."')";
$check_res = mysqli_query($mysqli, $sql) or die(mysqli_error($mysqli));
if ($check_res){
echo $newnum . " - CAN ISNERT#!#!#";
// close connection to datbase
mysqli_close($mysqli);
}
else{
echo "failed to enter into database";
// close connection to database
mysqli_close($mysqli);
}
break;
}
}
I would also like to note that this will continue to run if all the numbers have been used, you may want to put in something to track when all numbers have been used, and cause a break to jump out of the loop.
Hope this helps!
So I have a switch statement that I want to display one form or another based on if the id from one table has the matching foreign key in another table.
So far what I have tried is nesting one while statement into another which isn't working.
$subresult = mysqli_query($con,"SELECT * FROM tags GROUP BY tag");
$subresult2 = mysqli_query($con,"SELECT * FROM tag_subscribe WHERE uid = $uid");
while ($row = mysqli_fetch_array($subresult)) {
$tid = $row['tid'];
while ($row2 = mysqli_fetch_array($subresult2)) {
$tid2 = $row2['tid'];
}
if ($tid2 == $tid) {
$subbedup = 'yes';
} else {
$subbedup = 'no';
}
switch ($subbedup) {
case ('yes'):
echo "alternate html form goes here because $tid2 == $tid";
break;
case ('no'):
echo "html form goes here";
break;
}
}
So when this code is run, it only returns switch "no" except it will return one switch "yes" which just happens to be the last record of the second table that contains the foreign key. When I think about it, that makes sense as it will just keep running through this loop until it runs out of records in the table. So I spent about six minutes getting to this point and I have spent the last 6 hours trying to get it to work correctly without any luck.
So once again, fine people at SO, save me! Please and Thank you :)
So my question is: How would this be done correctly?
I'm not exactly sure of your database structure, so I'll improvise.
Given these sample tables and columns:
tags
id name
tag_subscriptions
user_id tag_id
The query below will loop through all tags. Each tag includes a subscribed column set to either "yes" or "no", depending on whether the current user is subscribed to that particular tag.
$sql="SELECT t.`id`, t.`name`, IF (ISNULL(ts.`tag_id`),'no','yes') AS `subscribed`
FROM `tags` t
LEFT JOIN `tag_subscriptions` ts ON (ts.`user_id`=$uid AND ts.`tag_id`=t.`id`)
WHERE 1;"
Then loop through all tags:
$q=mysql_query($sql) or die(mysql_error());
while ($row=mysql_fetch_assoc($q)) {
switch ($row['subscribed']) {
case 'yes'
// user is subscribed to this tag
break;
default:
// user is not subscribed to this tag
}
}
I think (hope) this is closer to what you're looking for.
http://sqlfiddle.com/#!2/58684/1/0
Sorry for using PDO as thats what i know, you can convert the idea to MYSQLi im sure.
$db = new PDO($hostname,$username,$password);
$arraySubTags = array();
$query = "SELECT tagID FROM tag_subscribe WHERE uid = :uid";
$statement = $db->prepare($query);
$statement->bindValue(':uid', $uid);
$statement->execute();
$subscribedTags = $statement->fetchAll(PDO::FETCH_ASSOC); //or loop with a while using fetch()
$statement->closeCursor();
foreach($subscribedTags as $sTag)
{
array_push($arraySubTags,$sTag);
}
$query = "SELECT * FROM tags GROUP BY tag";
$statement = $db->prepare($query);
$statement->execute();
$allTags = $statement->fetchAll(PDO::FETCH_ASSOC); //or loop with a while using fetch()
$statement->closeCursor();
foreach($allTags as $tag)
{
if(in_array($tag['tagID'], $arraySubTags))
{
echo "person is subscribed";
}else{ echo "person not subscribed";}
}
This code just checks whether the last tag checked is subscribed to - to check for each one you need to move the switch statement into the outer while loop, after the if..else bit that sets the $subbedup variable for the current tag.
Or you could make $subbedup an array, indexed by the tag id, if you need to keep the switch separate for some reason.
I need to use the goto operator in my code as I can't seem to think of a way around it. However the problem is my host only has PHP version 5.2.17 installed.
Any ideas?
Below is my code:
if ($ready !=="y")
{
$check=mysql_query("SELECT `inserted` FROM `team`");
$numrows = mysql_num_rows($check);
$i="0";
while ($i<$numrows && $row = mysql_fetch_assoc($check))
{
$array[$i] = $row['inserted'];
$i++;
}
if (in_array("n", $array))
{
goto skip;
}
else
{
mysql_query("
UPDATE game SET ready='y'
");
}
}
skip:
There are a few anti-patterns in your code. Let's clean it up. I'll explain what's been changed in a jiffy.
if($ready !== "y") {
$sth = mysql_query("SELECT inserted FROM team WHERE inserted = 'n'");
if(mysql_num_rows($sth) > 0) {
mysql_query("UPDATE game SET ready = 'y'");
}
}
First things first: There is no need to perform a query, fetch all of the results, then loop through those results (in_array) looking for a specific value. Let the database do that for you by expressly looking only for rows where inserted is the string literal "n".
Because we know that we're only getting "n" records back, we just need to check if there are any results. If so, run the query. If there are no "n" records, the UPDATE isn't run.
If you need to know that the UPDATE ran, add a check for it:
$ran_update = false;
if($ready !== "y") {
$sth = mysql_query("SELECT inserted FROM team WHERE inserted = 'n'");
if(mysql_num_rows($sth) > 0) {
mysql_query("UPDATE game SET ready = 'y'");
$ran_update = true;
}
}
if($ran_update) {
// ...
}
You want to use the correct control word to break from the loop:
if ($ready !=="y")
{
$check=mysql_query("SELECT `inserted` FROM `team`");
$numrows = mysql_num_rows($check);
$i="0";
while ($i<$numrows && $row = mysql_fetch_assoc($check))
{
$array[$i] = $row['inserted'];
$i++;
}
if (in_array("n", $array))
{
break;
}
else
{
mysql_query("
UPDATE game SET ready='y'
");
}
}
The break keyword will do exactly what you want: End the execution of the while loop. Never ever ever use a goto!
As a direct response to the title of this post:
do{
if (!$condition){
break;
}
// Code called if conditions above are met
}while(0);
//Code always called
In some circumstances, this, or a goto, can make for very tidy and readable code.
First, you could use a break to exit your initial loop. Second, if you need to test for anything, set a variable (must be global not local) as a flag or indicator before calling break, then do a conditional test statement where your skip line is to perform any additional steps you need.