To update multiple records in a MongoDB collection by their IDs and set a single field to the same value using PHP, you can utilize the `updateMany` method provided by the MongoDB PHP library.

Here’s how you can do it step-by-step:

1. Connect to MongoDB: First, ensure you have the MongoDB PHP driver installed and establish a connection to your MongoDB database.

2. Prepare the Update Query: You will need to specify the IDs of the documents you want to update and the field you want to set.

3. Execute the Update: Use the `updateMany` method to apply the changes.

Here’s a sample code snippet demonstrating this process:

require 'vendor/autoload.php'; // Composer autoload 
// Create a MongoDB client 
$client = new MongoDB\Client("mongodb://localhost:27017"); 
// Select the database and collection 
$collection = $client->yourDatabase->yourCollection;
// Define the IDs of the documents you want to update

$ids = [
new MongoDB\BSON\ObjectId('60c72b2f9b1e8b001c8e4e1a'),
new MongoDB\BSON\ObjectId('60c72b2f9b1e8b001c8e4e1b'),
new MongoDB\BSON\ObjectId('60c72b2f9b1e8b001c8e4e1c')
];

// Create the filter to match the documents by their IDs
$filter = ['_id' => ['$in' => $ids]];

// Define the update operation
$update = ['$set' => ['yourField' => 'newValue']];

// Execute the updateMany operation
$result = $collection->updateMany($filter, $update);

// Output the result
echo "Matched " . $result->getMatchedCount() . " documents and modified " . $result->getModifiedCount() . " documents.";

Explanation of the Code

– Connection: The code connects to a MongoDB instance running on `localhost` at port `27017`.
– Filter: The filter uses the `$in` operator to match documents whose `_id` is in the specified array of IDs.
– Update: The `$set` operator is used to update the specified field (`yourField`) to a new value (`newValue`).
– Execution: The `updateMany` method applies the update to all documents that match the filter.

This approach allows you to efficiently update multiple records in a single operation, ensuring that the specified field is set to the same value across all targeted documents.