How Can I Retrieve and Handle Query Errors from PDO's `prepare()` Method?

Obtaining Query Errors from prepare() in PDO PHP

When preparing a query using PDO, it can be essential to retrieve any associated errors. This is especially useful for debugging purposes or handling unexpected database interactions.

The Problem

Consider the following PHP code snippet:

$st = $db->prepare("SELECT * FROM c6ode");

In this case, if the query contains any errors (such as a non-existent table), it may be uncertain how to retrieve and handle those errors.

The Solution

To retrieve query errors from the prepare() method, it is necessary to configure PDO to throw exceptions on errors. This is achieved by setting the PDO::ATTR_ERRMODE attribute to PDO::ERRMODE_EXCEPTION.

Additionally, to ensure that the MySQL server validates the query during the preparation stage, it is crucial to disable the PDO::ATTR_EMULATE_PREPARES feature. This prevents the server from delaying query validation until execution.

To illustrate, consider the following code:

<?php
$pdo = new PDO('mysql:host=localhost;dbname=test;charset=utf8', 'localonly', 'localonly');
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$pdo->prepare('INSERT INTO DoesNotExist (x) VALUES (?)');

When this code is executed, an exception will be thrown with the following details:

SQLSTATE[42S02]: Base table or view not found: 1146 Table 'test.doesnotexist' doesn't exist

By configuring PDO appropriately, it becomes possible to capture and handle query errors effectively, ensuring efficient debugging and database interactions.

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