I want to print the convenient error message(user understandable message ) instead of PDO system fatel error.
I have the following PDO statement, if that table not exist I want to print error message table is not exist.
$db = new PDO('mysql:host=localhost;dbname=cnf20;charset=utf8mb4', 'root', '', array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
function getData($db) {
$stmt = $db->query("SELECT * FROM tb_accessory_info1");
return $stmt->fetchAll(PDO::FETCH_ASSOC);
}
try {
foreach(getData($db) as $row) {
echo $row['part_no'];
}
} catch(PDOException $ex) {
$db->rollBack();
echo $ex->getMessage();
}
Currently I'm getting this error message
Fatal error: Uncaught PDOException: There is no active transaction
in......on line 15
Instead of this I wanted to print user understandable error message like 'Please try again!'
Please support me! Thanks
As Paul said, it's not clear why you would want to query a table that doesn't exist, but one way is to check for the existence of the table in MySQL before running your other statements:
SELECT *
FROM `information_schema`.`tables`
WHERE `table_schema` = 'database_name' AND `table_name` = 'table_name'
LIMIT 1;
This assumes the user connecting to the database has read access on information_schema.tables. Replace 'database_name' and 'table_name' with your values.
Related
DB Type: MariaDB
Table Engine: InnoDB
I have a table where inside it has a column with a value which is being incremented (not auto, no inserting happens in this table)
When I run the following SQL query in phpMyAdmin it works just fine as it should:
UPDATE `my_table`
SET `my_column` = LAST_INSERT_ID(`my_column` + 1)
WHERE `my_column2` = 'abc';
SELECT LAST_INSERT_ID();
The above returns me the last value for the my_column table when the query happened. This query was taken directly from the mysql docs on locking: https://dev.mysql.com/doc/refman/8.0/en/innodb-locking-reads.html (to the bottom) and this seems to be the recommended way of working with counters when you don't want it to be affected by other connections.
My PDO:
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// set the PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "UPDATE `my_table`
SET `my_column` = LAST_INSERT_ID(`my_column` + 1)
WHERE `my_column2` = 'abc';
SELECT LAST_INSERT_ID();";
// Prepare statement
$stmt = $conn->prepare($sql);
// execute the query
$stmt->execute();
$result = $stmt->fetchColumn(); // causes general error
$result = $stmt->fetch(PDO::FETCH_ASSOC);// causes general error
// echo a message to say the UPDATE succeeded
echo $stmt->rowCount() . " records UPDATED successfully";
} catch(PDOException $e) {
echo $sql . "<br>" . $e->getMessage();
}
$conn = null;
Exact error SQLSTATE[HY000]: General error, If I remove the lines where I try to get the result, it updates the column, but I still do not have a return result... how do I perform that update query and get the select result all in one go like I do when I run it in phpMyAdmin? This all needs to happen in one go as specified by the MySQL docs so I don't have issues where two connections might get the same counter.
There is no need to perform SELECT LAST_INSERT_ID();. PDO will save that value automatically for you and you can get it out of PDO.
Simply do this:
$conn = new PDO("mysql:host=$servername;dbname=$dbname;charset=utf8mb4", $username, $password, [
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
]);
$sql = "UPDATE `my_table`
SET `my_column` = LAST_INSERT_ID(`my_column` + 1)
WHERE `my_column2` = 'abc'";
// Prepare statement
$stmt = $conn->prepare($sql);
// execute the query
$stmt->execute();
$newID = $conn->lastInsertId();
lastInsertId() will give you the value of the argument evaluated by LAST_INSERT_ID().
I'm having the problem of mySQL not recognizing the session user when I select data from a table. Can someone please point me in the correct position on what I need to do to fix this?
$sql1="SELECT * FROM `Bookings` WHERE `username`={$_SESSION['user']}";
This is what my code looks like, but it never fetches the data and just remains blank.
First you should check if $_SESSION['user'] is initialized or has any value.
Second, it is better to assign the session user to a variable, so as to avoid some ugly issues related to escaping quotes, in the future. Don't just directly dump your session within your mysql statement.
$user_session = $_SESSION['user'];
$sql1="SELECT * FROM `Bookings` WHERE `username`= $user_session";
#Edit:
as #Dann pointed out, it's must better and safer to user prepared statement, with either the mysqli/pdo API. Here is a simple example in PDO.
First you have to connect to your database:
try {
$db = new \PDO("mysql:host=localhost;dbname=xx;charset=utf8", "xx", "xx", [
PDO::ATTR_EMULATE_PREPARES => false,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
]);
} catch(\PDOException $e){
echo "Error connecting to mysql: ". $e->getMessage();
}
Then simply fetch the booking as seen below.
$user_session = $_SESSION['user'];
try{
$stmt = $db->prepare("SELECT * FROM Bookings WHERE username = ?");
$result = $stmt->execute([$user_session]);
if($result){
// show booking
}
} catch(\PDOException $e){
echo "Counld not get user bookings. error: " . $e->getMessage();
}
Now your query is safer from mysql injection attacks, and connection errors will only throw exceptions, instead of showing potentially harmful errors.
You can use
$user=$_SESSION['user'];
$sql1="SELECT * FROM Bookings WHERE username= '$user'";
Hopefully This will solve your problem
i am new to PDO.
Here is what i have done so far,
Created file "pdotest.php"
Code Inside that file
<?php
try {
$conn = new PDO('mysql:host=localhost;dbname=houserentsystem;charset=utf8', 'root', 'admin');
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e) {
echo 'ERROR: ' . $e->getMessage();
}
$stmt = $conn->query("SELECT roomName FROM roomName.roomnames");
$results = $stmt->fetchAll();
$stmt->closeCursor();
print_r($results);
var_dump($results);
it should display some results from database but instead it says 500 internal server error in firebug, but no error on screen, its a white blank screen.
$stmt = $conn->query("SELECT roomName FROM roomName.roomnames");
try this instead:
$stmt = $conn->query("SELECT roomName FROM roomnames");
The select syntax is (basically):
SELECT column[, another_column, ...] FROM tablename[WHERE condition][ORDER BY some_column ASC/DESC];`
As you are setting the error mode to PDO::ERRMODE_EXCEPTION, you'll need to use try/catch to see any errors. This brings the burden of wrapping try/catch statements around your db queries.
Check your php log file for the exact php error - a white screen is shown as php is probably set up not to display errors on screen.
I'd check this part:
SELECT roomName FROM roomName.roomnames
Are you really trying to select roomName column from a table named roomName.roomnames? Should it not be the other way around like
SELECT roomnames FROM roomName
?
I am using $insertedId = $pdo_conn->lastInsertId(); to get the last inserted ID after an insert query then i run another insert query:
foreach ($records as $emails_to) {
$stmt = $pdo_conn->prepare("INSERT into emails_to (email_seq, email) values (:email_seq, :email) ");
$stmt->execute(array(':email_seq' => $InsertedId, ':email' => $emails_to["email"]));
}
but it doesn't seem to recognise the last insert ID, i get this error:
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'email_seq' cannot be null'
what have i done wrong?
$insertedId and $InsertedId are not the same. Variable names are case-sensitive.
Your $insertedID doesn't match $InsertedID - case issue
edit; darn, beaten to the post
Beware of lastInsertId() when working with transactions in mysql. The following code returns 0 instead of the insert id.
This is an example
<?php
try {
$dbh = new PDO('mysql:host=localhost;dbname=test', 'username', 'password');
$stmt = $dbh->prepare("INSERT INTO test (name, email) VALUES(?,?)");
try {
$dbh->beginTransaction();
$stmt->execute( array('user', 'user#example.com'));
$dbh->commit();
print $dbh->lastInsertId();
}
catch(PDOException $e) {
$dbh->rollback();
print "Error!: " . $e->getMessage() . "</br>";
}
}
catch( PDOException $e ) {
print "Error!: " . $e->getMessage() . "</br>";
}
?>
When no exception is thrown, lastInsertId returns 0. However, if lastInsertId is called before calling commit, the right id is returned.
for more informations visit -> PHP
I'm trying to do a simple operation on a MySQL database: my contacts have their complete names on a column called first_name while the column last_name is empty.
So I want to take what's on the first_name column and split it on the first occurrence of a white space and put the first part on the first_name column and the second part on the last_name column.
I use the following code but it's not working:
$connection = new mysqli(DATABASE_SERVER, DATABASE_USERNAME, DATABASE_PASSWORD, DATABASE_NAME, DATABASE_PORT);
$statement = $connection->prepare("SELECT id, first_name FROM contacts");
$statement->execute();
$statement->bind_result($row->id, $row->firstName);
while ($statement->fetch()) {
$names = separateNames($row->firstName);
$connection->query('UPDATE contacts SET first_name="'.$names[0].'", last_name="'.$names[1].'" WHERE id='.$row->id);
}
$statement->free_result();
$statement->close();
$connection->close();
Can I use the $connection->query while having the statement open?
Best regards.
UPDATE
The $connection->query(...) returns FALSE and I get the following error:
PHP Fatal error: Uncaught exception 'Exception' with message 'MySQL Error - 2014 : Commands out of sync; you can't run this command now'
I changed the code to the following and worked:
$connection = new mysqli(DATABASE_SERVER, DATABASE_USERNAME, DATABASE_PASSWORD, DATABASE_NAME, DATABASE_PORT);
$result = $connection->query("SELECT id, first_name FROM contacts");
while ($row = $result->fetch_row()) {
$names = separateNames($row[1]);
$connection->query('UPDATE contacts SET first_name="'.$names[0].'", last_name="'.$names[1].'" WHERE id='.$row[0]);
}
$connection->close();
Can I use the $connection->query while having the statement open?
Yes. It will return a new result object or just a boolean depending on the SQL query, see http://php.net/mysqli_query - In your case of running an UPDATE query it will always return a boolean, FALSE if it failed, TRUE if it worked.
BTW, the Mysqli connection object is not the Mysqli statement object, so they normally do not interfere with each other (disconnecting might destroy/break some statements under circumstances, but I would consider this an edge-case for your question you can ignore for the moment).
I wonder why you ask actually. Maybe you should improve the way you do trouble-shooting?
I can only have one active statement at a given time, so I had to make one of the queries via the $connection->query() method.
As #hakre mentioned:
I still keep my suggestion that you should (must!) do prepared statements instead of query() to properly encode the update values
I opted to use the statement method for the update query, so the final working code is the following:
$connection = new mysqli(DATABASE_SERVER, DATABASE_USERNAME, DATABASE_PASSWORD, DATABASE_NAME, DATABASE_PORT);
$result = $connection->query("SELECT id, first_name FROM contacts");
$statement = $connection->prepare("UPDATE contacts SET first_name=?, last_name=? WHERE id=?");
while ($row = $result->fetch_row()) {
$names = separateNames($row[1]);
$statement->bind_param('ssi', $names[0], $names[1], $row[0]);
throwExceptionOnMySQLStatementError($statement, "Could not bind parameters", $logger);
$statement->execute();
throwExceptionOnMySQLStatementError($statement, "Could not execute", $logger);
}
$statement->free_result();
$statement->close();
$connection->close();
Thanks to all that gave their inputs, specially to #hakre that helped me to reach this final solution.