php - bindParam 和 bindValue 有什么区别？

Question

PDOStatement::bindParam() 之间有什么区别？和 PDOStatement::bindValue() ？

Answer 1

来自 the manual entry for PDOStatement::bindParam :

[With bindParam] Unlike PDOStatement::bindValue(), the variable is bound as a reference and will only be evaluated at the time that PDOStatement::execute() is called.

所以，例如:

$sex = 'male';
$s = $dbh->prepare('SELECT name FROM students WHERE sex = :sex');
$s->bindParam(':sex', $sex); // use bindParam to bind the variable
$sex = 'female';
$s->execute(); // executed with WHERE sex = 'female'

或

$sex = 'male';
$s = $dbh->prepare('SELECT name FROM students WHERE sex = :sex');
$s->bindValue(':sex', $sex); // use bindValue to bind the variable's value
$sex = 'female';
$s->execute(); // executed with WHERE sex = 'male'