I need some guidance on PDO error handling.
I got this code:
<?php
$config = include('config.php');
try{
$handler = new PDO('mysql:host-127.0.0.1;dbname=not_a_valid_dbname', $config->username, $config->password);
$handler->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo 'Yup!';
}catch(PDOException $e){
echo 'Caught! '.$e->getMessage();
}
As you can see I provided an unvalid db name. This page outputs 'Yup!' instead of letting me know that there is no such database. Same goes when changing 'mysql:not_valid_host'. Only when I change driver name it throws an error letting me know that there is no driver by that name.
I tried:
Checking php.ini for settigs (I have hard time getting around with this)
Adding
error_reporting(E_ALL);
ini_set("display_errors", 1);
ini_set("display_startup_errors", 1);
Adding
ini_set('display_errors',true);
Also tried adding a backslash in catch param:
catch(\PDOException $e)
Still the same result. Help me break my code :D
The documentation is very unclear, but I've made some tests and drawn some conclusions. This is pure speculation. I'll try to back some of these claims up if I find further information.
If host is not present, localhost is then assumed.
Database name is not mandatory. This is, I imagine, so you can connect to a server and create a new database through PDO.
If you have a syntax error, the string will stop being considered thereafter.
With those suppositions, we can assume why your code is working the way it is. Your DSN is:
mysql:host-127.0.0.1;dbname=not_a_valid_dbname
Since there's a syntax error (- after host), neither of the parameters are considered, and there's no DB selected, with the host being localhost. This is why you get no errors. If you delete the host parameter, however:
mysql:dbname=not_a_valid_dbname
localhost is used as host (selected by default), but not_a_valid_dbname is tried as the database, which results in
Caught! SQLSTATE[HY000] [1049] Unknown database '1234'
mysql:not_valid_host would be the same case as the first example. The DSN is invalid so localhost is assumed with no database selected.
Further, you get no error because no actual DB is selected but you didn't try to run a query. As soon as you do,
try {
$handler = new PDO('mysql:', "root", "root");
$handler->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$handler->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$handler->query("SELECT * FROM test");
echo 'Yup!';
} catch(PDOException $e) {
echo 'Caught! '.$e->getMessage();
}
You'll get an PDOException, as expected:
Caught! SQLSTATE[3D000]: Invalid catalog name: 1046 No database selected
Like I said, all of this is speculation as I couldn't really find concrete evidence on most of this. I hope this guides you in the right direction. I'll keep looking for more information and edit if I find anything.
Related
I'm using Jetbrains and Mysql to work on this practical project, but when I connect to the mysql
database it gives me the following error:
C:\wamp64\bin\php\php5.6.40\php.exe C:\wamp64\www\Social_Network\Includes\connection.php
Connection failed: SQLSTATE[HY000] [1049] Unknown database 'social_network'
Process finished with exit code 0
I made sure several times that the database name is the same name and there are
no spelling errors at all (I copy pasted it from the database)
Here's my code:
<?php
$servername = "localhost";
$username = "root";
$password = "";
try {
$conn = new PDO("mysql:host=$servername;dbname=social_network", $username, $password);
// set the PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "Connected successfully";
} catch (PDOException $e) {
echo "Connection failed: " . $e->getMessage();
}
//?>
Welll, there's little that can be done about it. MySQL thinks that the database does not exist.
is the server the correct one?
is the case sensitivity set correctly? "Social_Network" and "social_network" might be considered different.
can you access the database with those parameters using a different tool (e.g. HeidiSQL, SQLYog, SQLterm, in a pinch even phpMyAdmin)?
Actually, JetBrains PHPStorm has a SQL terminal utility that can diagnose the connection. You may want to use it (once it knows what database you're connecting to, it will also warn you of several possible errors such as using the wrong table name or column name).
I am trying to connect to my database with the following code. And it works, but I am not sure how secure is it. Do I must have a private function too? I don't have any examples of how to apply a private function on this code.
$username = 'user';
$dsn = 'mysql:host=localhost; dbname=register';
$password = 'somepassword';
try{
$db = new PDO($dsn, $username, $password);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}catch (PDOException $ex){
echo "Connection failed ".$ex->getMessage();
}
Better use php composer where you can put these details in a environment file .env. It will be secured as .env is hidden and is placed on Server.
Put the connection parameters into a secure place (i.e. not reachable
by HTTP requests, something like the first answer will be nice), don't leave them into PHP script or some file in the same context... if you put there, protect it with htaccess DENY directive
Never echo exceptions into script output, always deal with them (put
into a log file, translate to friendly errors hiding parameters,
etc). The script never should throw exceptions to the user, it must be handled... the user must only see friendly messages from the script, even a "Ops, something bad happen here..." is better than a "ERROR: SQLSTATE[42000] [1049] Unknown database 'users'" (that show the user a part of the database structure, witch is a security problem)
This is first post of a question. Tried to find an answer here, but all relevant posts seems dated or use deprecated mysql.
New to sqlite, so forgive what might appear stupid, but the query in the code below never works. Note: we are running sqlite3 and PDO on site with php 5.6.
A Program to create the db worked fine. And the app "Db Browser for SQL Lite" shows DB and tables and data just fine. But this:
<?php
//open the database
$myPDO = new PDO('sqlite:MySqlitedb1');
print "<p>db opened</p>";
$result = $myPDO->query('SELECT * FROM users');
//if the query works
if ($result !== FALSE) {
print "<p>query ran</p>";
foreach($result as $row){
print "<p>".$row."</p>";
}
} else {
// when the query fails
print "<p>query failed</p>";
} //end if
// close the database connection
$myPDO = NULL;
?>
Always results in a 'query failed'. Queries for specific records that ARE there also fails.
Also Tried some other testing in code above using fetch and fetchall, and they generated errors like:
mod_fcgid: stderr: PHP Fatal error: Call to a member function fetchAll()
on boolean in (path emoved)/testpdo2.php on line 27
Which I am sure was caused by the fact the query fails so $result is null/false
I am obviously missing something stupid here?
Joe C.
This is solved. The code should have worked (it does now). It was not
a directory issue
a permissions issue
a debug_kit.sqlite file in the tmp directory, or any files in the tmp dir.
a SCP or 'sync' directory issue
I altered the code and trapped an exception (1st with 'bad' DB then good one):
<?php
$myPDO = NULL; //close db just in case...
//open the database
$myPDO = new PDO('sqlite:newsqlite2.db');
//throw exceptions
$myPDO->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
if ($myPDO != null)
print "<p>db connected</p>";
else
print "<p>db did not connect</p>";
// result: db does open
//1st test
try
{
$result0=$myPDO->query('SELECT * from users');
print "<p>query ran</p>";
}
catch(PDOException $e)
{
echo "Statement failed: " . $e->getMessage();
return false;
}
// close the database connection
$myPDO = NULL;
?>
This threw an error with the original DB (MySqlitedb1) and an PDO exception:
SQLSTATE[HY000]: General error: 11 database disk image is malformed
Now, DESPITE analyse tools run on the database saying it was 'fine' and being able to work on the database with tools like "DB Browser for SQLite" without ANY issues, nor having issues creating other DB's, SOMETHING was amiss with the file. This caused the query's to fail and always return as a Boolean 'false', so the code failed.
We fixed the DB by dumping it to a sql file, then importing it (with "DB Browser for SQLite") to create a new database (newsqlite2.db), with the data. Using that DB, the code ran fine, extracted data etc.
As to why/how the database became "corrupt" or what the weird corruption was, I have not a clue. :)
Joe C.
I am new to web development, so probably there is something I am doing it wrong.
I am using webmatrix for development and playing around with StarterSite sample that webmatrix provides.
In one of the php file (header.php) there is a query to mysql using mysqli extension. I have changed the tablename to some non existent table to simulate error condition. The problem is, after below statement -
$statement->execute();
the script stops.
I inserted a echo statement after execute and that echo string is not displaying on webpage. However when I correct the table name, the echo string after execute is displayed on webpage. So I think the script stops executing after execute when the table name is wrong. I have two questions. How do I stop script from stop executing like this? Secondly How to know for sure that script has stopped executing at some particular statement?
For second part of question, I checked the log file and tracelog file in IISExpress folder. There is no mention of any error, probably because error happened in MYSQL. However, in my MYSQL folder there is no log file, so not sure how to check mysql log.
If I have missed anything, please let me know.
Regards,
Tushar
You should read about mysqli error handling.
Basic error handling example OOP:
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
Procedural:
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
It depends on what you're logging. In the error log you can define what's being logged. I think you can control the strict mode of the error in the php.ini which will automatically throw error into the access_log or error_log or apache log file.
The trick is to use $mysqli->error in every step of the mysqli querying and db connects to ensure you're getting proper error messages in detail whether to debug, improve the code or to do it correctly.
Here is an example of using $mysqli->error in querying the database.
$result = $mysqli->query($query);
if (!$result and $mysqliDebug) {
// the query failed and debugging is enabled
echo "<p>There was an error in query: $query</p>";
echo $mysqli->error; //additional error
}
You can also use a method where you define mysql error to be true in db conn
// define a variable to switch on/off error messages
$mysqliDebug = true;
// connect to your database
// if you use a single database, passing it will simplify your queries
$mysqli = #new mysqli('localhost', 'myuser', 'mypassword', 'mydatabase');
// mysqli->connect_errno will return zero if successful
if ($mysqli->connect_errno) {
echo '<p>There was an error connecting to the database!</p>';
if ($mysqliDebug) {
// mysqli->connect_error returns the latest error message,
// hopefully clarifying the problem
// NOTE: supported as of PHP 5.2.9
echo $mysqli->connect_error;
}
// since there is no database connection your queries will fail,
// quit processing
die();
}
#ref: https://www.daniweb.com/web-development/php/code/434480/using-phpmysqli-with-error-checking
I am trying to set up a new site on my hosting (Host route if it matters) but i keep getting this error when i try using PDO (first PDO site im trying):
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[3D000]: Invalid catalog name: 1046 No database selected' in /home/kennyi81/public_html/gamersite/login.php:36 Stack trace: #0 /home/kennyi81/public_html/gamersite/login.php(36): PDOStatement->execute() #1 {main} thrown in /home/kennyi81/public_html/gamersite/login.php on line 36
When i use these settings:
$dbh = new PDO("mysql:91.146.107.11;dbname=kennyi81_gamersite", "kennyi81_gamer", "***************");
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
....
$stmt = $dbh->prepare('SELECT * FROM USERS WHERE ID = :id LIMIT 1');
How the database is laid out:
I am able to use mysqli connect fine on my other sub domains / main site, but i just cannot get PDO to work.
I've tried this, which i have seen around:
$stmt = $dbh->prepare('SELECT * FROM gamersite.USERS WHERE ID = :id LIMIT 1');
but it retuns a syntax error.
Anyone have any idea what may be causing this?
This is all working on my local server, nothing changed on upload apart from connect line.
Instead of:
$dbh = new PDO("mysql:91.146.107.11;dbname=kennyi81_gamersite", "kennyi81_gamer", "***************");
Try:
$dbh = new PDO("mysql:host=91.146.107.11;dbname=kennyi81_gamersite", "kennyi81_gamer", "***************");
(add host=)
And it most likely works on your local server, because you have mysql:localhost... or mysql:127.0.0.1... there and it's ignored (cause it's missing host= aswell) and by default it's localhost.
From the PDO manual page, you can see that you need to wrap the connection in a try/catch block. This way if something goes wrong with the connection, it will tell you. Something like this:
try {
$dbh = new PDO("mysql:91.146.107.11;dbname=kennyi81_gamersite", "kennyi81_gamer", "***************");
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$dbh = null;
} catch (PDOException $e) {
print "Error!: " . $e->getMessage() . "<br/>";
// Then actually do something about the error
logError($e->getMessage(), __FILE__, __LINE__);
emailErrorToAdmin($e->getMessage(), __FILE__, __LINE__);
// etc.
die(); // Comment this out if you want the script to continue execution
}
The reason you are getting this error is because there is an error with your connection, but since you don't tell your script to stop, it doesn't. Look at the error message produced, and how to fix it should be made obvious. It appears that Michael Prajsnar's answer is correct in that you aren't setting a "host".
Edit:
As it turns out, PDO doesn't complain if you leave out your host or dbname in the PDO connection DSN part (at least on Unix). I tested it and leaving it blank will default it to "localhost" and I was therefore able to connect perfectly fine leaving this out completely for localhost connections, which would explain why it worked on your local server but not on your production server. In fact, it is completely possible to connect supplying absolutely nothing in the DSN except for the database engine like this:
$dbh = new PDO("mysql:", "kennyi81_gamer", "***************");
The only problem is that it won't be using a database, so to USE a database, just do:
if ($dbh->query("USE kennyi81_gamersite") === false)) {
// Handle the error
}
However with that said, I have my doubts that you actually tried connecting using a try/catch block (as you mention in your comments) unless you somehow provided valid database credentials. The ONLY way that doing it this way did not produce any sort of error is if you actually connected correctly and selected the database kennyi81_gamersite. If not, you would have seen a message like this:
Unable to connect to database. "mysql" said: SQLSTATE[28000] [1045]
Access denied for user 'kennyi81_gamer'#'localhost' (using password: YES)
In summary, always wrap your connection in a try/catch block if you want to find errors during connection. Just make sure not to re-throw (and not catch) the PDOException's getMessage() or you could expose your login credentials.