recovering from transaction failure in php - php

Question

SQL queries can fail for a number of reasons, even though the same query ran 100 times before without a problem. I'd like to detect weather a transaction failed. I found 2 ways of doing this:
1: use a ton of if else statements
$mysqli->begin_transaction();
$stmt = $mysqli->prepare("INSERT INTO testtable VALUES (?,?,?)");
if ( false===$stmt ) {
$mysqli->rollback();
issueInternalError();
}
$rc = $stmt->bind_param('iii', $x, $y, $z);
if ( false===$rc ) {
$mysqli->rollback();
issueInternalError();
}
$rc = $stmt->execute();
if ( false===$rc ) {
$mysqli->rollback();
issueInternalError();
}else{
$mysqli->commit();
}
$stmt->close();
2: perform query in try catch block
try{
$mysqli->begin_transaction();
$stmt = $mysqli->prepare("INSERT INTO testtable VALUES (?,?,?)");
$stmt->bind_param('iii', $x, $y, $z);
$stmt->execute();
$mysqli->commit();
}catch(Exception $e){
$mysqli->rollback();
issueInternalError();
}
Using try/catch halves the code and it makes it really readable, but will the second code correctly catch all possible errors? or better will issueInternalError() always be executed if an error exists?
UPDATE:
I've added this code to the beginning of php file
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
I am getting mixed results in my tests:
This kind of error is catched successfully:
$mysqli->begin_transaction();
$stmt = $mysqli->prepare("INSERT INTO testtable VALUES (?,?,?)");
$stmt->bind_param('iiissss', $x, $y, $z); //error here is successfully catched
but this isn't
$mysqli->begin_transaction();
$stmt = $mysqli->prepare("INSERT INTO testtable VALUES (?,?,?)");
$stmt->bind_param('iii', $x, $y, $z,""); //error not catched
It looks like the second one is not caused by mysqli, therefore it isn't thrown.

Answer 1

Your try-catch will not catch all errors. It will only catch exceptions. There's a difference between errors and exceptions in PHP.
The following try-catch will catch only exceptions:
try {
// ...
} catch(Exception $e) {
// ...
}
To catch both exceptions and errors you can use Throwable interface. As a side note, it is best to always provide fully specified name for classes and interfaces in PHP.
try {
// ...
} catch(\Throwable $e) {
// ...
}
Mysqli can throw both exceptions and errors. Exceptions are usually triggered when mysqli can't process a command or the execution of the command failed on the MySQL server-side. These exceptions are instances of mysqli_sql_exception exception class.
If there is a programmer error on the PHP side, e.g. an incorrect number of arguments or invalid arguments, then mysqli will trigger a PHP error. These can be various errors, but usually, they all derive from the base class Error.
Warning: Prior to PHP 8 many errors were simply warnings. These have been properly categorized now. Additionally, a number of software bugs were fixed in mysqli that didn't trigger an exception when one should occur. For best result, please use the latest PHP release.