Concatenating fields of mongo db using php

Question

I am trying to concatenate two fields in mongo db using php for a huge data set. Below is the sample solution that I have found and tried so far but this doesn't works in php. Can anyone help with the necessary corrections if any in the below code.

var pipeline = [
        {
           "$project": {
            "data1": 1,
            "data2": { $concat: [ "$data1", " ", "$data2" ] }
            }
        }
],
cursor = db.collection.aggregate(pipeline),
bulkUpdateOps = cursor.map(function (doc) { 
    return { 
            "updateOne": {
                "filter": { "_id": doc._id },
                "update": { "$set": { "data2": doc.data2 } } 
             }
          };
});         
db.collection.bulkWrite(bulkUpdateOps);

I am installing mongo-php-library as you suggested in comments by using the composer command :

$composer require "mongodb/mongodb=^1.0.0" 

but it didnt work. php mongo driver is 1.6.12. and mongo db version is 3.2.3 . and the error is as follows :

 Your version of PHP, 5.4.16, is affected by CVE-2013-6420 and cannot safely perform certificate validation, we strongly suggest you upgrade.
  ./composer.json has been created
 Loading composer repositories with package information
 Updating dependencies (including require-dev)
 Your requirements could not be resolved to an installable set of packages.

  Problem 1

     - mongodb/mongodb 1.0.1 requires ext-mongodb ^1.1.0 -> the requested PHP extension mongodb is missing from your system.

     - mongodb/mongodb 1.0.0 requires ext-mongodb ^1.1.0 -> the requested PHP extension mongodb is missing from your system.

- Installation request for mongodb/mongodb ^1.0.0 -> satisfiable by mongodb/mongodb[1.0.0, 1.0.1].
  To enable extensions, verify that they are enabled in those .ini files:

- /etc/php.ini

- /etc/php.d/curl.ini

- /etc/php.d/dom.ini

- /etc/php.d/fileinfo.ini

- /etc/php.d/json.ini

- /etc/php.d/mbstring.ini

- /etc/php.d/mysql.ini

- /etc/php.d/mysqli.ini

- /etc/php.d/pdo.ini

- /etc/php.d/pdo_mysql.ini

- /etc/php.d/pdo_sqlite.ini

- /etc/php.d/phar.ini

- /etc/php.d/posix.ini

- /etc/php.d/sqlite3.ini

- /etc/php.d/sysvmsg.ini

- /etc/php.d/sysvsem.ini

- /etc/php.d/sysvshm.ini

- /etc/php.d/wddx.ini

- /etc/php.d/xmlreader.ini

- /etc/php.d/xmlwriter.ini

- /etc/php.d/xsl.ini

- /etc/php.d/zip.ini

  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

   Installation failed, deleting ./composer.json.

I need a help in installing this library. Am I installing the wrong version?

Answer 1

Thank you all for the help but I could not install the mongo php library so the above solution didn't work for me. I found another way that I would like to share to merge two fields which used the shell commands. In php file :

$concat_Command = "mongo < concat.sql";
shell_exec($concat_Command);

concat.sql

 use dbname;
 db.collection.find().forEach(function(doc){
    db.collection.update(
        { "_id": doc._id },
        { "$set": { "description": doc.title+" "+doc.description } }
    )
});

Answer 2

Without seeing your attempts at solving this in PHP, much of what follows is based on assumptions and may therefore not offer the best solution but will nonetheless serve as a guideline to sway you in the right direction to solve your issue.

Using the PHP driver with the complimentary mongo-php-library, which implements a more full-featured API on top of the bare-bones driver, construct the aggregation pipeline and the subsequent bulk update operation as:

$pipeline = [["$project" => ["data1" => 1, "data2" => ["$concat" => [ "$data1", " ", "$data2" ]]]]];
$operation = new Aggregate($databaseName, $collectionName, $pipeline, ['typeMap' => $typeMap]);
$cursor = $operation->execute($primaryServer);
$results = iterator_to_array($cursor);

function mapper($doc) {
    return [
        "updateOne" => [
            ["_id" => $doc["_id"]], 
            [
                "$set" => [
                    "data2" => $doc["_id"]
                ]
            ]
        ]
    ]
};

$ops = array_map("mapper", $results);
$bulkUpdateOps = new BulkWrite($databaseName, $collectionName, $ops);
$writeResult = $bulkUpdateOps->execute($primaryServer);

In the above, $primaryServer is a parameter for the BulkWrite execute() method that should contain an instance of the MongoDB\Driver\Server object i.e. your primary MongoDB server connection details. The $typeMap variable is an optional parameter in the Aggregate() constructor to denote Type map for BSON deserialization. This will be applied to the returned cursor.

---

If you're using the legacy driver then consider running the following operation which uses the Bulk Operations API which is available from MongoDB >= 2.6 <= 3.0:

$client = new MongoClient();
$collection = $client->selectCollection("database", "collection");

$pipeline = array(         
    array(
        "$project" => array(
            'data1' => 1,
            "data2" => array("$concat" => array( "$data1", " ", "$data2" ))
        )
    )
);

$batch = new MongoUpdateBatch($collection);
$counter = 0;

foreach ($collection->aggregate($pipeline) as $doc ) {
    $batch->add(
        array(
            "q" => array( '_id' => $doc['_id'] ),
            "u" => array( 
                '$set' => array(
                    "data2" => $doc["data2"]
                )
            )
        )
    );
    $counter++;

    if ($counter % 500 === 0) {
        $retval = $batch->execute(array( 'w' => 1));
        $counter++;
        $batch = new MongoUpdateBatch($collection);        
    }
}

if ($counter > 0) {
    $retval = $batch->execute(array( 'w' => 1 ));
}