I have the following code, I am unable to figure out why the PDO statement error occurs, here is my code
try {
$db = new PDO("mysql:dbname=imdb","username","pwd");
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$first_name=$db->quote($first_name);
$last_name=$db->quote($last_name);
$row_id=$db->query("SELECT id FROM actors WHERE last_name=$last_name AND first_name LIKE ${first_name} ORDER BY film_count DESC LIMIT 1");
if ($row_id->rowCount() > 0) {
$idrow=$row_id->fetch_assoc();
print_r($idrow);
return $row_id;
}
else {
return Null;
}
}
catch (PDOException $ex) {
?>
<p>Sorry, a database error occurred. Please try again later.</p>
<p>(Error details: <?= $ex->getMessage() ?>)</p>
<?php
return NULL;
}
I get this error when I run
Fatal error: Call to undefined method PDOStatement::fetch_assoc()
Any help?
Because just like the error says. fetch_assoc() isn't defined.
You want
$row_id->fetch(PDO::FETCH_ASSOC)
fetch() is the correct method name and you pass it one of the PDO Constants to determine what type of variable to get back.
Related
I've got a (example) Oracle Stored Procedure:
CREATE OR REPLACE FUNCTION EXCEPTION_TEST
RETURN NUMBER
AS
BEGIN
raise_application_error(-20500, 'This is the exception text I want to print.');
END;
and I call it in PHP with PDO with the following code:
$statement = $conn->prepare('SELECT exception_test() FROM dual');
$statement->execute();
The call of the function works perfectly fine, but now I want to print the Exception text only.
I read somewhere, that you should not use try and catch with PDO. How can I do this?
You have read that you shouldn't catch an error to report it.
However, if you want to handle it somehow, it's all right to catch it.
Based on the example from my article on handling exception in PDO,
try {
$statement = $conn->prepare('SELECT exception_test() FROM dual');
$statement->execute();
} catch (PDOException $e) {
if ($e->getCode() == 20500 ) {
echo $e->getmessage();
} else {
throw $e;
}
}
Here you are either getting your particular error or re-throwing the exception back to make it handled the usual way
You check the execute response and get the error, for example, like this:
if ($statement->execute() != true) {
echo $statement->errorCode();
echo $statement->errorInfo();
}
You can find more options at the PDO manual.
This question already has answers here:
pdo - Call to a member function prepare() on a non-object [duplicate]
(8 answers)
Closed 6 years ago.
I'm writing a function to check for records in my database before executing anything, and i'm getting the error Call to a member function prepare() which i don't quite understand. I've been struggeling for quite some time now, and i'd really appriciate some help
The problem should be with the prepare() in line 19
<?php
$dsn = "xxx"; // Database Source Name
$username="xxx"; // User with acress to database. Root is MySQL admin.
$password="xxx"; //The user password.
try {
$conn = new PDO($dsn, $username, $password);
$conn ->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e) {
echo "Connection failed: ".$e->getMessage();
}
//------------------------ Does the category already exist? -------------------------
function checkuser($fbid,$fbfname,$fblname,$femail) {
$sql="SELECT COUNT(*) AS subjectcount FROM Users WHERE Fuid=:Fuid";
try {
$stmt = $conn->prepare($sql);
$stmt->bindValue(":Fuid",$_SESSION['FBID'], PDO::PARAM_INT);
$stmt->execute();
$row = $stmt->fetch(PDO::FETCH_ASSOC);
$subjectcount=$row["subjectcount"];
} catch (PDOException $e) {
echo "Server Error - try again!".$e->getMessage();
}
//------------------------ If it dosn't, insert it -------------------------
if ($subjectcount==0) {
And i'm having a hard time debugging since i dont quite understand the cause of this error.
I updated my code to
<?php
$dsn = "xxx"; // Database Source Name
$username="xxx"; // User with acress to database. Root is MySQL admin.
$password="xxx"; //The user password.
try {
$conn = new PDO($dsn, $username, $password);
$conn ->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e) {
echo "Connection failed: ".$e->getMessage();
}
//------------------------ Does the category already exist? -------------------------
function checkuser($fbid,$fbfname,$fblname,$femail) {
global $conn;
$sql="SELECT COUNT(*) AS subjectcount FROM Users WHERE Fuid=:Fuid";
try {
$stmt = $conn->prepare($sql);
$stmt->bindValue(":Fuid",$_SESSION['FBID'], PDO::PARAM_INT);
$stmt->execute();
$row = $stmt->fetch(PDO::FETCH_ASSOC);
$subjectcount=$row["subjectcount"];
} catch (PDOException $e) {
echo "Server Error - try again!".$e->getMessage();
exit;
}
//------------------------ If it dosn't, insert it -------------------------
if ($subjectcount==0) {
I guess the full error message is:
Fatal error: Call to a member function prepare() on a non-object
Right?
You are calling the member function (= function which is a member of a class instance) prepare of the variable $conn which is not declared in the scope of your checkuser function, it's declared outside (in global scope)!
To "import" it into your function so you can access it, put this line at the top of your function:
global $conn;
Also, it looks like you don't have full error reporting enabled, otherwise you would have seen this error before the fatal one, giving you another clue:
Notice: Undefined variable: conn
(By the way, you should exit; after outputing the DB error message in your catch block - otherwise you will print the error but continue to the rest, with a nonexisting DB connection!)
I can't seem to use a array in a PDO statement here. It connects to the SQL Server properly, I just removed the user pass for security. When I run this script, it returns:
Call to undefined method PDOStatement::prepare()
I have no idea what I'm doing wrong. I've researched everywhere. Any help would be appreciated.
<?php
$hello = "foo";
try {
$bdd = new PDO("mysql:host=sql213.byethost16.com;dbname=b16_16742662_main", "b16_16742662", "00163827");
} catch(Exception $e){
die("ERROR : ".$e->getMessage());
}
$req = $bdd->prepare("SELECT * FROM ajax_chat_registered_members WHERE NAME=:UserName AND PASS=:UserPass");
$req->prepare(array('UserName'=>"Test",'UserPass'=>"foo"));
?>
I'm executing MySQL database querys in my PHP scrpt like this:
function doStuffInDB(){
...
if (($r = mysqli_query($db_conn, $q)) === false) {
throw new Exception(mysqli_error($db_conn));
} else {
//get result
}
...
}
When I call the function which executes the query, I call it like this:
function doStuff(){
try{
doStuffInDB();
}catch(Exception $e){
echo $e->getMessage();
}
}
I would like to write a generic error handler that takes the error number of the error that occurred and returns an error message to the user. Something like:
function doStuff(){
try{
doStuffInDB();
}catch(Exception $e){
echo $feedback = handleError($e->getErrorNumber());
}
}
For me to do this, I need a list of error numbers which can occur while calling mysqli_query() but I can not find any such list. Where can I find this documentation? Any tip on how this error handler (a php function) would look like?
I'm using the following script to use a database using PHP:
try{
$db = new PDO('mysql:host='.$host.';port='.$port.';dbname='.$db, $user, $pass, $options);
}
catch(Exception $e){
$GLOBALS['errors'][] = $e;
}
Now, I want to use this database handle to do a request using this code:
try{
$query = $db->prepare("INSERT INTO users (...) VALUES (...);");
$query->execute(array(
'...' => $...,
'...' => $...
));
}
catch(Exception $e){
$GLOBALS['errors'][] = $e;
}
Here is the problem:
When the connection to the DB is OK, everything works,
When the connection fails but I don't use the DB, I have the $GLOBALS['errors'][] array and the script is still running afterwards,
When the connection to the DB has failed, I get the following fatal error:
Notice: Undefined variable: db in C:\xampp\htdocs[...]\test.php on line 32
Fatal error: Call to a member function prepare() on a non-object in C:\xampp\htdocs[...]\test.php on line 32
Note: Line 32 is the $query = $db->prepare(...) instruction.
That is to say, the script crashes, and the try/catch seems to be useless. Do you know why this second try/catch don't works and how to solve it?
Thanks for the help!
EDIT: There are some really good replies. I've validated one which is not exactly what I wanted to do, but which is probably the best approach.
try/catch blocks only work for thrown exceptions (throw Exception or a subclass of Exception must be called). You cannot catch fatal errors using try/catch.
If your DB connection cannot be established, I would consider it fatal since you probably need your DB to do anything meaningful on the page.
PDO will throw an exception if the connection cannot be established. Your specific problem is that $db is not defined when you try to call a method with it so you get a null pointer (sort of) which is fatal. Rather than jump through if ($db == null) hoops as others are suggesting, you should just fix your code to make sure that $db is either always defined when you need it or have a less fragile way of making sure a DB connection is available in the code that uses it.
If you really want to "catch" fatal errors, use set_error_handler, but this still stops script execution on fatal errors.
In PHP7, we now can using try catch fatal error with simple work
try {
do some thing evil
} catch (Error $e) {
echo 'Now you can catch me!';
}
But usualy, we should avoid using catch Error, because it involve to miss code which is belong to programmer's reponsibility :-)
I will not report what has already been written about testing if $db is empty. Just add that a "clean" solution is to artificially create an exception if the connection to the database failed:
if ($db == NULL) throw new Exception('Connection failed.');
Insert the previous line in the try - catch as follow:
try{
// This line create an exception if $db is empty
if ($db == NULL) throw new Exception('Connection failed.');
$query = $db->prepare("INSERT INTO users (...) VALUES (...);");
$query->execute(array(
'...' => $...,
'...' => $...
));
}
catch(Exception $e){
$GLOBALS['errors'][] = $e;
}
Hope this will help others!
If database connection fails, $db from your first try .. catch block will be null. That's why later you cannot use a member of non-object, in your case $db->prepare(...). Before using this add
if ($db) {
// other try catch statement
}
This will ensure that you have db instance to work with it.
Try adding the following if statement :
if ($db) {
$query = $db->prepare("INSERT INTO users (...) VALUES (...);");
$query->execute(....);
}
else die('Connection lost');
try{
if(!is_null($db))
{
$query = $db->prepare("INSERT INTO users (...) VALUES (...);");
$query->execute(array(
'...' => $...,
'...' => $...
));
}
}
catch(Exception $e){
$GLOBALS['errors'][] = $e;
}