About setting error levels

Question

$dsn = "mysql:host=localhost;dbname=lamp25;charset=utf8";

$pdo = new PDO($dsn, 'root', '123');

//Set error level

$pdo->setAttribute(3, 2);

##Can I ask about the previous paragraph? What are 3 and 2? Can you tell me in detail?

#The manual seems to be in English. . . .

Answer 1

$pdo->setAttribute(PDO::ATTR_CASE, PDO::CASE_NATURAL); You can use static class constants like PDO::ATTR_CASE instead of numbers. It’s not clear what 3 and 2 are. It is more intuitive to write English letters.