What are common debugging techniques for PHP code that interacts with a database?

One common debugging technique for PHP code that interacts with a database is to check for errors in the SQL query syntax. This can be done by printing out the query string and running it directly in the database management tool to see if there are any syntax errors. Another technique is to check for errors in the connection to the database, such as incorrect credentials or server configuration issues. Additionally, logging errors and exceptions can help identify issues with database interactions. 

// Example code snippet for debugging SQL query syntax errors
$query = "SELECT * FROM users WHERE id = $user_id";
echo $query; // Print out the query string to check for syntax errors

// Example code snippet for debugging database connection issues
$connection = mysqli_connect("localhost", "username", "password", "database");
if (!$connection) {
    die("Connection failed: " . mysqli_connect_error());
}

// Example code snippet for logging errors and exceptions
try {
    // Database interaction code here
} catch (Exception $e) {
    error_log($e->getMessage());
}

Keywords

SQL injection error handling PDO mysqli database connection

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