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PHP - Using PDO with IN clause array
(9 answers)
Closed 24 days ago.
I did have this code working but it was not secure from SQL injection so I tried to update it. The user submit filter requirements which come from check boxes, I take them from post, and replace them with ?, I then implode, and bind them back together for the IN clause.
I feel like I am a couple of lines of code away from getting this. What am I doing wrong? I have echoed out after implode and it shows the right amount of ? corresponding to the selections. Is the problem in my execute statement?
if(isset($_POST['songgenre'])){
$songgenre = $_POST['songgenre'];
$placeholderssonggenre = array_fill(1, count($songgenre), '?');
$songgenrefilter = implode(',', $placeholderssonggenre);
}else{
$songgenre ='';
$genreempty = '';
}
$sql = "SELECT * FROM music_db WHERE songgenre IN ($songgenrefilter)";
$stmt = $conn->prepare($sql);
$res = $stmt->execute($songgenre);
if ($res !== FALSE) {
$results = $res->rowCount();
echo($results);
} else {
echo "Code Failed";
}
I know really how frustrating it could be. Well, it seems that following things are missing there. Try it:
When you're using the IN clause, you need to pass an array of values to the execute() method, not a single variable. This means that you should be passing $songgenre directly to the execute() method, instead of using it to create the $placeholderssonggenre variable.
You should bind the parameters to the statement before executing it, not after. You can use the bindValue() method to bind the values to the placeholders in the query.
When you execute the statement, you should use the fetchAll() method to retrieve the rows, instead of rowCount().
Here's the correct code:
if(isset($_POST['songgenre'])){
$songgenre = $_POST['songgenre'];
$placeholders = array_fill(0, count($songgenre), '?');
$placeholders = implode(',', $placeholders);
} else {
$songgenre ='';
$placeholders = '';
}
$sql = "SELECT * FROM music_db WHERE songgenre IN ($placeholders)";
$stmt = $conn->prepare($sql);
foreach ($songgenre as $i => $value) {
$stmt->bindValue($i + 1, $value);
}
$stmt->execute();
$results = $stmt->fetchAll();
Another option more elegant
if(isset($_POST['songgenre'])){
$postfilter = [
'songgenre' => ['filter' => FILTER_SANITIZE_STRING] // always sanitize
];
$filter_post_array = filter_var_array($_POST, $postfilter);
$filtered = $filter_post_array['songgenre'];
} else {
$filtered = [];
}
$sql = "SELECT * FROM music_db WHERE songgenre IN (:songgenrefilter)";
$stmt = $conn->prepare($sql);
$stmt->bindValue(':songgenrefilter',implode(',',$filtered);
$stmt->execute();
$result = $stmt->fetchAll();
I have an array, which includes an insertId (as a key) several other values; this needs to be submitted as a $key=> $value array (e.g. 1 => 2, 1 =>3, 1=>5) etc.
However, when I bind the parameters within the foreach loop, I keep getting an array to string conversion error. as a result I get one row being inserted into the db (the correct key,and then a 0).
function instructorSubject()
{
$query = "INSERT into instructor_has_subject
SET instructor_id = :instructor_id,
subject_id = :id";
$last_id = $this->conn->lastInsertId();
$stmt = $this->conn->prepare($query);
//print_r($last_id);
//print_r($this->id);
if (isset($this->id) && $this->id != '') {
foreach ($_POST as $values) {
$stmt->bindParam(":instructor_id", $last_id, PDO::PARAM_INT);
$stmt->bindParam(":id", $this->id, PDO::PARAM_INT);
}
if($stmt->execute())
{
return true;
}
else
{
var_dump($stmt);
print_r($stmt->errorInfo());
return false;
}
}
}
A sample array is something like this:
the insert id: 87
and then the second array appearing as a straight forward key=>value pair (for example:)
( [0] => 1 [1] => 3 )
I feel it has something to do with where I'm binding within the foreach. thanks in advance for any assistance.
After speaking to you in chat, this is the solution we came up with.
function instructorSubject()
{
$query = "INSERT INTO instructor_has_subject (instructor_id, subject_id) VALUES (?,?)";
$last_id = $this->conn->lastInsertId();
$stmt = $this->conn->prepare($query);
if(!empty($this->id)) {
foreach($_POST['subject_id'] as $id) {
$stmt->execute(array(
$last_id,
$id
));
}
}
}
The main thing we changed I believe was changing $_POST to $_POST['subject_id'].
We also removed bindParam completely from the function, instead opting for unnamed parameters and passing the variables via execute() inside the loop.
I'm trying to create a reusable code in PDO.
here's my code.
$myClass = new main_c();
$condition = "email_address = :email_address AND password = :password";
$array = array('email_address' => 'yiihii#yahoo.com', 'password' => '98467a817e2ff8c8377c1bf085da7138');
$row = $myClass->get('user', $condition, $array, $db);
print_r($row);
Here's my function.
public function get($tablename, $condition, $array, $db){
$stmt = $db->prepare("SELECT * FROM $tablename WHERE $condition");
foreach($array as $k=>$v){
$stmt->bindParam(":$k", $v);
}
try{
$stmt->execute();
}catch(PDOException $e){
$error = new main_c();
echo $error->error_handling($e);
}
return $row=$stmt->fetch(PDO::FETCH_ASSOC);
}
I've tried omitting the AND in the condition and just put a single where clause and it worked. I think there's a problem in the foreach. i'm not sure though.
You are not binding values, but parameters, so in your loop you are only binding one variable $v to key $k. Twice. And by the time you execute your query these variables will contain the values of the last iteration of the loop.
You would need to change bindParam() to bindValue().
However, as you are not using the third parameter of bindParam() / bindValue() - forcing a data type - you can skip that whole loop and do:
try {
$stmt = $db->prepare("SELECT * FROM $tablename WHERE $condition");
$stmt->execute($array);
...
As I am writing a script, I am typing $db->prepare()'s and $stmt->bindParam()'s constantly. I am looking for a way to consolidate it all in a function. This is what I have so far.
$sql = "SELECT (name, email) FROM users WHERE VALUES (:name, :email)"
$values = array(':name' => 'my_name', ':email' => 'blahblah#example.com', );
function db_query($sql, $values) {
global $db; //Database object
$stmt = $db->prepare($sql);
foreach($values as $placeholder => $value) {
$stmt->bindParam($placeholder, $value);
}
$stmt->execute();
$result = $stmt->fetchAll(PDO::FETCH_ASSOC);
return $result;
}
Would this be sufficient for most queries? Is this a secure way to do this?
I just want the query to run and return whatever it returns (NULL, values, error, etc...).
Thanks.
Your code will not work as expected because bindParam() binds the placeholder name (first argument) to the variable reference present in the second argument.
Using your example, this would result in all parameters set to blahblah#example.com as it is the last $value in the loop.
As mentioned in the comments, simply use $stmt->execute($values). See http://php.net/manual/en/pdostatement.execute.php
If you really want to continue with your loop, use PDOStatement::bindValue() instead.
Please see below my code.
I am attempting to bind an array of paramenters to my prepared statement.
I've been looking around on the web and can see I have to use call_user_func_array but cannot get it to work. The error I get is:
"First argument is expected to be a valid callback, 'Array' was given"
I may be wrong but I'm assuming the first argument can be an an array and perhaps this error message is misleading. I think the issue is that my array is in someway at fault.
Can anyone see what I am doing wrong? Thanks.
$type = array("s", "s");
$param = array("string1","anotherstring");
$stmt = $SQLConnection->prepare("INSERT INTO mytable (comp, addl) VALUES (?,?)");
$params = array_merge($type, $param);
call_user_func_array(array(&$stmt, 'bind_param'), $params);
$SQLConnection->execute();
It must be like this:
//connect
$mysqli = new mysqli($host, $user, $password, $db_name);
//prepare
$stmt = $mysqli->prepare("SELECT * FROM the_table WHERE field1= ? AND Field2= ?");
//Binding parameters. Types: s = string, i = integer, d = double, b = blob
$params= array("ss","string_1","string_2");
//now we need to add references
$tmp = array();
foreach($params as $key => $value) $tmp[$key] = &$params[$key];
// now us the new array
call_user_func_array(array($stmt, 'bind_param'), $tmp);
$stmt->execute();
/* Fetch result to array */
$res = $stmt->get_result();
while($row = $res->fetch_array(MYSQLI_ASSOC)) {
$a_data[]=$row;
}
print_r($a_data);
$stmt->close();
Since PHP 5.6, you don't have to mess around with call_user_func_array() anymore.
Instead of:
$stmt->bind_param($param_types, $my_params_array);
you can just use the splat operator, like this:
$stmt->bind_param($param_types, ...$my_params_array); // exact code
I wouldn't know why you have to use call_user_func_array, but that's another story.
The only thing that could be wrong in my eyes is that you are using a reference to the object. Assuming you're using PHP 5.*, that is not necessary:
call_user_func_array(array($stmt, 'bind_param'), $params);
If you get an error, you should try this:
call_user_func_array(array($stmt, 'bind_param'), refValues($params));
function refValues($arr){
if (strnatcmp(phpversion(),'5.3') >= 0) {
$refs = array();
foreach($arr as $key => $value)
$refs[$key] = &$arr[$key];
return $refs;
}
return $arr;
}
Wasn't able to answer this on my own question because it got marked as dupe: here. But I think my final solution, which uses the answers in this question, works in my use case, might be helpful for someone.
My goals was to take a posted set of ID's and use them in a NOT IN MYSQL statement. Assuming array of 5 ID's posted.
Count the number posted ID's to build the ? placeholders for NOT IN statement. Using $params_count = substr(str_repeat(',?', count($array_of_ids)), 1); gives the result: (?,?,?,?,?) to be used in SQL statement.
Make function that takes ID's and type i or s etc. For me, they were all i so my function is simpler. return array that looks like this $params= array("iiiii",1,2,3,4,5) where the first value is the set of i's and the subsequent values are the ID's depending on total ID's passed into function.
function build_bind_params($values, $bind_type) {
$s = substr(str_repeat($bind_type, count($values)), 0);
$bind_array = array();
$bind_array[] = $s;
foreach($values as $value) {
$bind_array[] = $value;
}
return $bind_array;
}
$params = build_bind_params($array_of_ids, "i");
Then use foreach ($params as $key => $value) $tmp[$key] = &$params[$key]; to get the newly created $params formatted properly for binding.
Then use call_user_func_array(array($stmt , 'bind_param') , $tmp); to properly bind the array.
Then execute the $stmt
Most of the above are not solutions without integrating the types along with the values before adding them to call_user_func_array(). This solution worked for me:
/* create a database connection */
$db = new mysqli($host, $user, $password, $db_name);
/* setup the sql, values, and types */
$sql="SELECT * FROM languages
WHERE language_code = ?
AND charset = ?
ORDER BY native_name";
$values = array($langCode, $charset);
$types = "ss";
/* pass those variables to the execute() function defined below */
if ($rows = execute($sql, $values, $types))
{
return $rows[0];
}
function execute($sql, $values='', $types='')
{
/* prepare the sql before binding values and types */
$stmt = $db->prepare($sql);
/*combine the values and types into $inputArray */
$inputArray[] = &$types;
$j = count($values);
for($i=0;$i<$j;$i++){
$inputArray[] = &$values[$i];
}
/* add the combined values and types to call_user_func_array() for binding */
call_user_func_array(array($stmt, 'bind_param'), $inputArray);
$result = $stmt->execute();
return $result;
}
Here's a reference to the full description this example is based on:
http://big.info/2015/08/php-use-call_user_func_array-for-variable-number-of-parameters-arrays-in-prepared-statements.html
Why would you want to call call_user_func_array(array($statement, 'bind_param'), $bind_arguments)? Because $bind_arguments is an array. You get to have one function that binds a statement to its queried parameters, no matter how many parameters you'd have otherwise.
Example of good code...
<?php
# link
$dblink = new mysqli('HOSTNAME','USERNAME','PASSWORD','DATABASENAME');
# example data
$statement = $dblink->prepare("SELECT * from Person WHERE FirstName = ? AND MiddleName = ? AND LastName = ? and Age = ?");
$recordvalues = ['John', 'H.', 'Smith', 25];
$sqlbindstring = "sssi"; # String, String, String, Integer example
# make the references
$bind_arguments = [];
$bind_arguments[] = $sqlbindstring;
foreach ($recordvalues as $recordkey => $recordvalue)
{
$bind_arguments[] = & $recordvalues[$recordkey]; # bind to array ref, not to the temporary $recordvalue
}
# query the db
call_user_func_array(array($statement, 'bind_param'), $bind_arguments); # bind arguments
$statement->execute(); # run statement
$result = $statement->get_result(); # get results
# get the results
if($result) {
while ($row = $result->fetch_assoc()) {
print("\n\nMy row is...");
print_r($row);
}
}
?>
Example of bad code...
<?php
# Same setup as above..
$statement->prepare("SELECT * from Person WHERE FirstName = ? AND MiddleName = ? AND LastName = ? and Age = ?");
$statement->bind('John', 'H.", 'Smith', 25);
?>
In the first example: You can pass as much or as little to the binding to be done, so that bind() might be called in only one line in your entire application. This scales well.
In the second example: You must write one bind() statement for every possible group of insertions for every possible record in your database. This scales poorly.