In what situations would using a SQL-Abstraction-Layer like Doctrine be beneficial for PHP developers working with different database types?

Using a SQL-Abstraction-Layer like Doctrine can be beneficial for PHP developers working with different database types because it allows them to write database queries in a database-agnostic way. This means that developers can write queries using Doctrine's QueryBuilder or DQL without having to worry about the specific syntax differences between different database systems. Additionally, Doctrine provides features like entity mapping and caching, which can help improve performance and simplify database interactions.

// Example code snippet using Doctrine QueryBuilder to fetch data from a database

use Doctrine\DBAL\DriverManager;
use Doctrine\DBAL\Query\QueryBuilder;

// Create a Doctrine DBAL connection
$connectionParams = [
    'dbname' => 'my_database',
    'user' => 'root',
    'password' => 'password',
    'host' => 'localhost',
    'driver' => 'pdo_mysql',
];
$conn = DriverManager::getConnection($connectionParams);

// Create a QueryBuilder instance
$qb = $conn->createQueryBuilder();

// Build a query using QueryBuilder
$qb->select('*')
   ->from('users')
   ->where('age > :age')
   ->setParameter('age', 18);

// Execute the query and fetch results
$results = $qb->execute()->fetchAll();

// Loop through the results
foreach ($results as $result) {
    echo $result['name'] . ' - ' . $result['email'] . '<br>';
}