I am using a PHP PDO driver for an application that uses Apache Cassandra and I cannot fetch the information I need. Is anything obviously wrong?
$db = new PDO('cassandra:host=localhost;port=9160');
$db->exec("USE project");
$st = $db->prepare("SELECT fname FROM users WHERE email=:em;");
$st->bindValue(':em', 'email1#gmail.com', PDO::PARAM_STR);
$st->execute();
print_r($st->fetch(PDO::FETCH_ASSOC));
Nothing is printed to the window. The table users was created with the email column as the primary key. I had no trouble inserting and updating information to the users table in my app, but still cannot figure out how to fetch single values successfully. Similarly, when I fetchAll() with some query I can print the arrays (rows) to the screen but cannot index them to grab specific values. Maybe there is some detail about cassandra that I am missing?
Do the following:
Check the return values of each method.
Check if there is an error after executing the statement.
Check the error log of your php interpreter.
$db = new PDO('cassandra:host=localhost;port=9160');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
$db->exec("USE project");
$st = $db->prepare("SELECT fname FROM users WHERE email=:em;");
if ($st == false) {
print_r($db->errorInfo())
exit;
}
if ($st->bindValue(':em', 'email1#gmail.com', PDO::PARAM_STR) == false) {
print_r($db->errorInfo())
exit;
}
if ($st->execute() == false) {
print_r($db->errorInfo())
exit;
}
print_r($st->fetch(PDO::FETCH_ASSOC));
I had a similar problem. I used YACassandraPDO. Unfortunately when use it with php 5.4 I get error 502. Decided to write his or her library that allowed to work with Cassandra binary protocol without experiencing similar problems.
In the future, I plan to speed it up.
Maybe it will help you. Syntax like PDO.
Related
I have a simple form that needs a list of stops in the textarea and returns an id for each on the right hand side. This is my screenshot on localhost...I have the same table names, column names, number of records on both localhost and live server.
Here's the screenshot of the same page with same query on live server...
Here's the code I am using on both pages
$conn = new PDO("mysql:host=$host;dbname=$db;charset=$charset", $user, $pass);
if(isset($_POST["busnumber"], $_POST["busroute"])){
$stops = explode(PHP_EOL, $_POST["busroute"]);
$sql = 'SELECT * FROM stops WHERE stop_name LIKE :stop';
$statement = $conn->prepare($sql);
$statement->setFetchMode(PDO::FETCH_ASSOC);
foreach($stops as $stop){
$statement->bindValue(':stop', $stop);
$statement->execute();
$results = $statement->fetchAll();
foreach($results as $result){
echo $result['stop_id'].' '.$result['stop_name']."</br>";
}
}
}
As you can see, it returns the ID of the last row only on the live server. Can someone please tell me how this is possible and what I am missing?
EDIT 1
Notice what happens when I reverse the data entered in the text area
The localhost shows both the ids now
Guess what the server shows after reversing? Only the LAST ROW!
You don't need setFetchMode(). In the time I've used PDO I always had the best results with just using bindParam() and fetch() with the most default setup of PDO, which means just setting the errormode to exception and charset to utf8 like this:
try
{
$con = new PDO("mysql:host=".$host.";dbname=".$db_name, $user, $password);
}
catch(PDOException $e){
die("ERROR ". $e->getMessage());
}
$con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$con->exec("SET NAMES utf8");
Fetching any results like this
while($r = $statement->fetch())
{
echo $r['id'];
}
Any time when someone has used a different set up, I've noticed they've faced problems.
Try this, perhaps.
This is very simple. Please check your live db via phpmyadmin if you have access and from phpmyadmin run your queries like you are running it from php code. May be you have some restrictions of mysql or php on live. And also check your db versions on localhost and live with php versions too. Let me know the results of phpmyadmin queries thanks!
Just guessing the problem. I don't really think if this answer is correct. So please pardon me in advance.
PDOStatement::fetchAll() returns an array that consists of all the rows returned by the query. From this fact we can make two conclusions:
This function should not be used, if many rows has been selected. In
such a case conventional while loop ave to be used, fetching rows
one by one instead of getting them all into array at once. "Many"
means more than it is suitable to be shown on the average web page.
This function is mostly useful in a modern web application that
never outputs data right away during fetching, but rather passes it
to template.
Source: PDO Tutorial
I FIXED the error. I have answered it in detail on a different post and I am linking to that post from HERE Thank you all for your time and answers
I am attempting to create new tables every time I post to this method, but for some reason I can not figure out why it dies.
<?php
$host = "127.0.0.1";
$username = 'cotten3128';
$pwd = 'pwd';
$database = "student_cotten3128";
$pin = $_REQUEST['pinSent'];
$words = $_REQUEST['resultSent'];
$tableName = $pin;
$db = new mysqli($host, $username, $pwd, $database);
if ($sql = $db->prepare("CREATE TABLE $pin (id INT(11) AUTO_INCREMENT);")) {
$sql->execute();
$sql->close();
}else{
echo $mysql->error;
die('Could not create table');
}
for($i=0;$i<count($words);$i++){
if($sql = $db->prepare("INSERT INTO ".$pin.$words[$i].";")) {
$sql->execute();
$sql->close();
}else{
echo $mysql->error;
die("Could not add data to table");
}
}
mysqli_close();
?>
Any help or insight would be greatly appreciated.
The intention of my post is to help you finding the issue by yourself. As you did not added much information I assume my post is helpful for you.
Based on the code you have shared I guess you mean one of your called die() functions is executed.
Wrong function call
As Jay Blancherd mentioned mysql_close is the wrong function. You rather have to use mysqli_close as you created a mysqli instance.
Beside of that mysql_* is deprecated and should not be used anymore.
Debugging Steps
Not only for this case but in general you should ask yourself:
Is there an error message available? (Frontend output, error log file, ...)
YES:
What's the message about?
Is it an error you can search for? E.g. via a search engine or the corresponding documentation?
Look up in the bug tracker (if available), by the software developer of the software you are using, and if it has not been reported yet report the issue.
NO: (if none error message available OR you cannot search for it as it is a custom error message)
Search in the files of the software you are using for the error message and start a core-debugging.
STILL NO SOLUTION?:
Ask on stackoverflow.com e.g. and tell your issue and the steps you have performed to find and fix the bug. Post only as much code as necessary plus use a proper format.
Debugging in your case:
In order to narrow down the scope. Which of the die() is executed? Depending on that echo the query to execute just before it actually is executed. Then copy the SQL query to an SQL editor and look at it syntax. After that you probably know the problem already.
I know this is probably something simple, but I have searched for hours the past few days and I'm ready to jump out of my one-story building.
Have a basic site for testing, literally nothing on it but opening/closing html tags.
A very basic table in a data base, using phpmyadmin to access it.
Trying to get table contents to display on the basic website.
Was using mysqli_ or mysql_ style in the php to access the data for a while with no luck.. Have since been reading about PDO and found numerous tutorials on how to use it. I feel like what I'm trying to do should be so simple but I've tried copying what I've found on this site and other tutorials to the T and the site still does not display the data.
try {
$conn = new PDO("mysql:host=$hostname; dbname=$userdb", $username, $password);
$conn->exec("SET CHARACTER SET utf8");
$sql = "SELECT * FROM Monday";
$result = $conn->query($sql);
while($row = $result->fetchAll(PDO::FETCH_ASSOC)) {
echo $row['Name'] . '<br />';
}
$conn = null;
}
catch(PDOException $e) {
echo $e->getMessage();
}
Basically the website will display everything after the first -> in this case after the $conn-> but none of the actual table data.
I've tried about 50 different ways at least from numerous sites and I'm just lost now I guess..
Side note: I do have php forms on the same site that when submitted successfully insert data into the table, so I know I am able to connect to the db and table and INSERT, its just the issue of SELECT I can't get.
Thanks for any help
EDITED: to add fetchAll
You are using the method fetch() in your loop, which only fetches the next single row of your results. Replace it with fetchAll() and it should work.
More information about the fetchAll() method:
http://php.net/manual/en/pdostatement.fetchall.php
And for testing purposes you could set the PDO error mode to PDO::ERRMODE_EXCEPTION. See: http://php.net/manual/en/pdo.error-handling.php
while($row = $result->fetch(PDO::FETCH_ASSOC)) {
Should be;
while($row = $result->fetchAll(PDO::FETCH_ASSOC)) {
As part of a PHP web application, I'm querying a MySQL database using mysqli and prepared statements.
I've used exactly the same code on a few queries and it works, but on one particular query, it always returns an empty record set. I've run exactly the same query from the MySQL command line, and it correctly returns the result. I've checked the parameters being passed in, and they're fine.
I've spent the best part of a day trying to figure out why I'm always getting an empty record set with no errors or warnings. I've got PHP's errors set to display on the page, and I've got them set to E_ALL|E_STRICT. I still don't get any warnings or errors.
I've tried all the obvious things, like making sure I can actually connect to the database, checking the parameters that are being passed in, and making sure the row I'm trying to return actually exists in the database. I've had var_dump()s and die()s all over the page to check what's coming back, and it's always a legitimate, but empty, recordset.
function salt() {
return("I've removed my salt from this sample code");
}
function openDatabase() {
$conn = new mysqli("127.0.0.1", "username", "password", "database")
or die("Error: Could not connect to database.");
return($conn);
}
function checkUserCredentials($username, $password) {
$goodPassword = md5(salt().$username.$password);
$conn = openDatabase();
$query = $conn->stmt_init();
$query->prepare("SELECT id FROM users WHERE email = ? AND passwordHash = ?")
or die('Problem with query');
$query->bind_param("ss", $username, $goodPassword)
or die('Error binding parameters');
$query->execute() or die("Could not execute");
$query->bind_result($col1) or die ("Could not bind result");
if ($col1 !== 0) {
die("Authentication Complete");
} else {
die("Authentication Failure! Number of Rows: ".$query->num_rows." Username: " . $username . " Password Hash: " . $goodPassword);
}
}
Any feedback is appreciated. I'm sure I'm missing something simple, but if I didn't shave my head I'd be tearing my hair out right now.
Thanks
I'm not familiar with the mysqli library (I usually use PDO which provides a very similar cross platform API) so I can't immediately see any problem. However, you might try watching the mysqld log. See here for info:
http://dev.mysql.com/doc/refman/5.1/en/query-log.html
By tailing the log, you should be able to see the exact query that was submitted.
One final note, I notice you're using a fixed salt value. Wouldn't it be better to generate this value randomly each time you need it and then store it in the users table? Generally, a salt is not intended to be secret, it's just there to prevent people precomputing tables of passwords using the hash algorithm that you use.
In case anyone else runs into similar issues, it really helps if you run fetch() on your mysqli_stmt object.
In my code above, the solution looks like this:
$query->bind_result($col1) or die ("Could not bind result");
$query->fetch(); // <--- How could I forget to do this?
if ($col1 !== 0) {
return true;
} else {
return false;
}
Added on behalf of OP
I'm trying to get into PDO details. So I coded this:
$cn = getConnection();
// get table sequence
$comando = "call p_generate_seq('bitacora')";
$id = getValue($cn, $comando);
//$comando = 'INSERT INTO dsa_bitacora (id, estado, fch_creacion) VALUES (?, ?, ?)';
$comando = 'INSERT INTO dsa_bitacora (id, estado, fch_creacion) VALUES (:id, :estado, :fch_creacion)';
$parametros = array (
':id'=> (int)$id,
':estado'=>1,
':fch_creacion'=>date('Y-m-d H:i:s')
);
execWithParameters($cn, $comando, $parametros);
my getValue function works fine, and I get the next sequence for the table. But when I get into execWithParameters, i get this exception:
PDOException: SQLSTATE[HY000]: General error: 2014 Cannot execute queries while other unbuffered queries are active. Consider using PDOStatement::fetchAll(). Alternatively, if your code is only ever going to run against mysql, you may enable query buffering by setting the PDO::MYSQL_ATTR_USE_BUFFERED_QUERY attribute. in D:\Servidor\xampp_1_7_1\htdocs\bitacora\func_db.php on line 77
I tried to modify the connection attributes but it doesn't work.
These are my core db functions:
function getConnection() {
try {
$cn = new PDO("mysql:host=$host;dbname=$bd", $usuario, $clave, array(
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
));
$cn->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true);
return $cn;
} catch (PDOException $e) {
print "Error!: " . $e->getMessage() . "<br/>";
die();
}
}
function getValue($cn, $comando) {
$resul = $cn->query($comando);
if (!$resul) return null;
while($res = $resul->fetch()) {
$retorno = $res[0][0];
break;
}
return $retorno;
}
function execWithParameters($cn, $comando, $parametros) {
$q = $cn->prepare($comando);
$q->execute($parametros);
if ($q->errorInfo() != null) {
$e = $q->errorInfo();
echo $e[0].':'.$e[1].':'.$e[2];
}
}
Somebody who can shed a light for this? PD. Please do not suggest doing autonumeric id, cause i am porting from another system.
The issue is that mysql only allows for one outstanding cursor at a given time. By using the fetch() method and not consuming all the pending data, you are leaving a cursor open.
The recommended approach is to consume all the data using the fetchAll() method.
An alternative is to use the closeCursor() method.
If you change this function, I think you will be happier:
<?php
function getValue($cn, $comando) {
$resul = $cn->query($comando);
if (!$resul) return null;
foreach ($resul->fetchAll() as $res) {
$retorno = $res[0];
break;
}
return $retorno;
}
?>
I don't think PDOStatement::closeCursor() would work if you're not doing a query that returns data (i.e. an UPDATE, INSERT, etc).
A better solution is to simply unset() your PDOStatement object after calling PDOStatement::execute():
$stmt = $pdo->prepare('UPDATE users SET active = 1');
$stmt->execute();
unset($stmt);
The problem seems to be---I'm not too familiar with PDO--- that after your getValue call returns, the query is still bound to the connection (You only ever ask for the first value, yet the connection returns several, or expects to do so).
Perhaps getValue can be fixed by adding
$resul->closeCursor();
before the return.
Otherwise, if queries to getValue will always return a single (or few enough) value, it seems that using fetchAll will be preferred.
I just spend 15 minutes googling all around the internet, and viewed at least 5 different Stackoverflow questions, some who claimed my bug apparently arose from the wrong version of PHP, wrong version of MySQL library or any other magical black-box stuff...
I changed all my code into using "fetchAll" and I even called closeCursor() and unset() on the query object after each and every query. I was honestly getting desperate! I also tried the MYSQL_ATTR_USE_BUFFERED_QUERY flag, but it did not work.
FINALLY I threw everything out the window and looked at the PHP error, and tracked the line of code where it happened.
SELECT AVG((original_bytes-new_bytes)/original_bytes) as saving
FROM (SELECT original_bytes, new_bytes FROM jobs ORDER BY id DESC LIMIT 100) AS t1
Anyway, the problem happened because my original_bytes and new_bytes both where unsigned bigints, and that meant that if I ever had a job where the new_bytes where actually LARGER than the original_bytes, then I would have a nasty MySQL "out of range" error. And that just happened randomly after running my minification service for a little while.
Why the hell I got this weird MySQL error instead of just giving me the plain error, is beyond me! It actually showed up in SQLBuddy (lightweight PHPMyAdmin) when I ran the raw query.
I had PDO exceptions on, so it should have just given me the MySQL error.
Never mind, the bottom line is:
If you ever get this error, be sure to check that your raw MySQL is actually correct and STILL working!!!
A friend of mine had very much the same problem with the xampp 1.7.1 build. After replacing xampp/php/* by the 5.2.9-2 php.net build and copying all necessary files to xampp/apache/bin it worked fine.
If you're using XAMPP 1.7.1, you just need to upgrade to 1.7.2.