# MongoDB\Driver\ReadConcern::isDefault

(mongodb >=1.3.0)

MongoDB\Driver\ReadConcern::isDefault — Checks if this is the default read concern

### Descripción

final public MongoDB\Driver\ReadConcern::isDefault(): bool

Returns whether this is the default read concern (i.e. no options are specified). This method is primarily intended to be used in conjunction with MongoDB\Driver\Manager::getReadConcern() to determine whether the Manager has been constructed without any read concern options.

The driver will not include a default read concern in its read operations (e.g. MongoDB\Driver\Manager::executeQuery()) in order order to allow the server to apply its own default. Libraries that access the Manager's read concern to include it in their own read commands should use this method to ensure that default read concerns are left unset.

### Parámetros

Esta función no tiene parámetros.

### Valores devueltos

Returns `true` if this is the default read concern and `false` otherwise.

### Errores/Excepciones

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

### Ejemplos

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

`<?php
$rc = new MongoDB\Driver\ReadConcern(null);
var_dump($rc->isDefault());
$rc = new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::MAJORITY);
var_dump($rc->isDefault());
$manager = new MongoDB\Driver\Manager('mongodb://127.0.0.1/?readConcernLevel=majority');
$rc = $manager->getReadConcern();
var_dump($rc->isDefault());
$manager = new MongoDB\Driver\Manager('mongodb://127.0.0.1/');
$rc = $manager->getReadConcern();
var_dump($rc->isDefault());
?>`

El resultado del ejemplo sería:

    bool(true)
    bool(false)
    bool(false)
    bool(true)

### Ver también

- MongoDB\Driver\Manager::getReadConcern() - Return the ReadConcern for the Manager
- » Read Concern reference