# MongoDB\Driver\ReadConcern::__construct

(mongodb >=1.0.0)

MongoDB\Driver\ReadConcern::__construct — Create a new ReadConcern

### Descripción

final public MongoDB\Driver\ReadConcern::__construct(?string `$level` = `null`)

Constructs a new MongoDB\Driver\ReadConcern, which is an immutable value object.

### Parámetros

`level`

  The » read concern level. You may use, but are not limited to, one of the class constants.

### Errores/Excepciones

- Lanza una MongoDB\Driver\Exception\InvalidArgumentException en errores de análisis de argumentos.

### Ejemplos

Ejemplo #1 MongoDB\Driver\ReadConcern::__construct() example

`<?php
/* Unspecified read isolation level (uses the server's default behavior) */
$rc = new MongoDB\Driver\ReadConcern();
/* Request read isolation from a single replica set node */
$rc = new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::LOCAL);
/* Request read isolation from a majority of the replica set nodes */
$rc = new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::MAJORITY);
?>`

### Ver también

- » Read Concern reference