Hướng dẫn php fatal error example

I'm using the following script to use a database using PHP:

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• Table of Contents
• Global exception handler
• Can we catch fatal error in PHP?
• How can I get 500 error in PHP?
• What does fatal error mean in PHP?
• How do I fix uncaught error in 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.

demis dot palma at tiscali dot it ¶

6 years ago

Throwable does not work on PHP 5.x.

To catch both exceptions and errors in PHP 5.x and 7, add a catch block for Exception AFTER catching Throwable first.
Once PHP 5.x support is no longer needed, the block catching Exception can be removed.

try
{
   // Code that may throw an Exception or Error.
}
catch [Throwable $t]
{
   // Executed only in PHP 7, will not match in PHP 5
}
catch [Exception $e]
{
   // Executed only in PHP 5, will not be reached in PHP 7
}

lubaev dot ka at gmail dot com ¶

5 years ago

php 7.1

try {
   // Code that may throw an Exception or ArithmeticError.
} catch [ArithmeticError | Exception $e] {
   // pass
}

diogoca at gmail dot com ¶

2 years ago

Examples

Example #4 Throwing an Exception

The above example will output:

0.2
Caught exception: Division by zero.
Hello World

Example #5 Exception handling with a finally block

The above example will output:

0.2
First finally.
Caught exception: Division by zero.
Second finally.
Hello World

Example #6 Interaction between the finally block and return

The above example will output:

Example #7 Nested Exception

The above example will output:

Example #8 Multi catch exception handling

The above example will output:

Example #9 Omitting the caught variable

Only permitted in PHP 8.0.0 and later.