Replace Documents

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Overview

Sample Data
Replace Operation
Required Parameters
Return Value
Example
Modify the Replace Operation
Example
Additional Information
API Documentation

Overview

In this guide, you can learn how to use the MongoDB PHP Library to run a replace operation on a MongoDB collection. A replace operation performs differently than an update operation. An update operation modifies only the specified fields in a target document. A replace operation removes all fields in the target document and replaces them with new ones.

To replace a document, use the MongoDB\Collection::replaceOne() method.

Sample Data

The examples in this guide use the restaurants collection in the sample_restaurants database from the Atlas sample datasets. To access this collection from your PHP application, instantiate a MongoDB\Client that connects to an Atlas cluster and assign the following value to your $collection variable:

$collection = $client->sample_restaurants->restaurants;

To learn how to create a free MongoDB Atlas cluster and load the sample datasets, see the Get Started with Atlas guide.

Replace Operation

You can perform a replace operation by using MongoDB\Collection::replaceOne(). This method removes all fields except the _id field from the first document that matches the search criteria. It then inserts the fields and values you specify into the document.

Required Parameters

The replaceOne() method requires the following parameters:

Query filter document, which determines the documents to replace. For more information about query filters, see the Query Filter Documents section in the MongoDB Server manual.
Replace document, which specifies the fields and values to insert in the new document.

Return Value

The replaceOne() method returns a MongoDB\UpdateResult object. The MongoDB\UpdateResult type contains the following methods:

Method	Description
`getMatchedCount()`	Returns the number of documents that matched the query filter, regardless of how many were updated.
`getModifiedCount()`	Returns the number of documents modified by the update operation. If an updated document is identical to the original, it is not included in this count.
`getUpsertedCount()`	Returns the number of documents upserted into the database, if any.
`getUpsertedId()`	Returns the ID of the document that was upserted in the database, if the driver performed an upsert.
`isAcknowledged()`	Returns a boolean indicating whether the write operation was acknowledged.

Example

The following example uses the replaceOne() method to replace the fields and values of a document in which the name field value is 'Pizza Town'. It then prints the number of modified documents:

$replace_document = [
    'name' => 'Mongo\'s Pizza',
    'cuisine' => 'Pizza',
    'address' => [
        'street' => '123 Pizza St',
        'zipCode' => '10003',
    ],
    'borough' => 'Manhattan'
];
$result = $collection->replaceOne(['name' => 'Pizza Town'], $replace_document);
echo 'Modified documents: ', $result->getModifiedCount();

Modified documents: 1

Important

The values of _id fields are immutable. If your replacement document specifies a value for the _id field, it must match the _id value of the existing document.

Modify the Replace Operation

You can modify the behavior of the MongoDB\Collection::replaceOne() method by passing an array that specifies option values as a parameter. The following table describes some options you can set in the array:

Option	Description
`upsert`	Specifies whether the replace operation performs an upsert operation if no documents match the query filter. For more information, see the upsert statement in the MongoDB Server manual. Defaults to `false`.
`bypassDocumentValidation`	Specifies whether the replace operation bypasses document validation. This lets you replace documents that don't meet the schema validation requirements, if any exist. For more information about schema validation, see Schema Validation in the MongoDB Server manual. Defaults to `false`.
`collation`	Specifies the kind of language collation to use when sorting results. For more information, see Collation in the MongoDB Server manual.
`hint`	Gets or sets the index to scan for documents. For more information, see the hint statement in the MongoDB Server manual.
`session`	Specifies the client session to associate with the operation.
`let`	Specifies a document with a list of values to improve operation readability. Values must be constant or closed expressions that don't reference document fields. For more information, see the let statement in the MongoDB Server manual.
`comment`	Attaches a comment to the operation. For more information, see the insert command fields guide in the MongoDB Server manual.

Example

The following code uses the replaceOne() method to find the first document in which the name field has the value 'Food Town', then replaces this document with a new document in which the name value is 'Food World'. Because the upsert option is set to true, the library inserts a new document if the query filter doesn't match any existing documents:

$replace_document = [
    'name' => 'Food World',
    'cuisine' => 'Mixed',
    'address' => [
        'street' => '123 Food St',
        'zipCode' => '10003',
    ],
    'borough' => 'Manhattan'
];
$result = $collection->replaceOne(
    ['name' => 'Food Town'],
    $replace_document,
    ['upsert' => true]
);

Additional Information

To learn more about update operations, see the Update Documents guide.

To learn more about creating query filters, see the Specify a Query guide.

API Documentation

To learn more about any of the methods or types discussed in this guide, see the following API documentation:

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