yii\db\Command::prepare PHP Méthode

prepare() public méthode

For complex SQL statement that is to be executed multiple times, this may improve performance. For SQL statement with binding parameters, this method is invoked automatically.
public prepare ( boolean $forRead = null )
$forRead boolean whether this method is called for a read query. If null, it means the SQL statement should be used to determine whether it is for read or write.
    public function prepare($forRead = null)
    {
        if ($this->pdoStatement) {
            $this->bindPendingParams();
            return;
        }
        $sql = $this->getSql();
        if ($this->db->getTransaction()) {
            // master is in a transaction. use the same connection.
            $forRead = false;
        }
        if ($forRead || $forRead === null && $this->db->getSchema()->isReadQuery($sql)) {
            $pdo = $this->db->getSlavePdo();
        } else {
            $pdo = $this->db->getMasterPdo();
        }
        try {
            $this->pdoStatement = $pdo->prepare($sql);
            $this->bindPendingParams();
        } catch (\Exception $e) {
            $message = $e->getMessage() . "\nFailed to prepare SQL: {$sql}";
            $errorInfo = $e instanceof \PDOException ? $e->errorInfo : null;
            throw new Exception($message, $errorInfo, (int) $e->getCode(), $e);
        }
    }