Question

I ve the following content in mongo db collection,

{ "_id" : ObjectId("5052f343381ef8bc10000011"), "first_name" : "Tadataka", "midle_name"  :      
"", "last_name" : "Yamada", "title" : "Independent Director", "biogra
phy" : "Dr. Tadataka Yamada, M.D., is Independent Director of Agilent Technologi
es Inc., ", "rank" : " ", "department" : " ", "current" : "true", "company_id" :     ObjectId("50072714b4a6deba100051d3"
) } }

When I tried to update the above content for few fields and also insert new field if not exist, the existing fields get over written. Here is my code,

$mycollection->update(array("_id" => $id), array('$set' => array("first_name" => $first_name, "updated_at" => $uat));

and the result I am getting is

{ "_id" : ObjectId("5052f343381ef8bc10000011"), "first_name" : "Tadataka", "updated_at" : 134567894 }

Instead of updating just the values, my whole content gets overwritten, where I am missing.?

Answer 1

The update() in the code you shared is correct. Since you’re using an atomic modifier, $set, there is no reason that the entire document for the given _id would be overwritten. The following script easily reproduces this, and outputs the example document with its first_name field altered and updated_at field added:

<?php

$m = new Mongo();
$c = $m->test->foo;
$c->drop();

$document = array(
    '_id' => new MongoId('5052f343381ef8bc10000011'),
    'first_name' => 'Tadataka',
    'middle_name' => '',
    'last_name' => 'Yamada',
    'title' => 'Independent Director',
    'company_id' => new MongoId('50072714b4a6deba100051d3')
);

$c->insert($document);

$c->update(
    array('_id' => $document['_id']),
    array('$set' => array('first_name' => 'foobar', 'updated_at' => new MongoDate()))
);

var_dump($c->findOne());

If you run this locally, you should see:

array(7) {
  ["_id"]=>
  object(MongoId)#8 (1) {
    ["$id"]=>
    string(24) "5052f343381ef8bc10000011"
  }
  ["company_id"]=>
  object(MongoId)#9 (1) {
    ["$id"]=>
    string(24) "50072714b4a6deba100051d3"
  }
  ["first_name"]=>
  string(6) "foobar"
  ["last_name"]=>
  string(6) "Yamada"
  ["midle_name"]=>
  string(0) ""
  ["title"]=>
  string(20) "Independent Director"
  ["update_at"]=>
  object(MongoDate)#10 (2) {
    ["sec"]=>
    int(1347908855)
    ["usec"]=>
    int(551000)
  }
}

It would probably be helpful if you shared how you obtained the last result you pasted, but your update query certainly isn’t to blame here.

As a side note, you likely want to use a proper boolean value for the current field in your document instead of the string "true".