mongoDB update multiple fields in single array element (from form) -


i've seen many variations on question, none specific issue. consider following document:

{     "class" : "english101",     "students" : [         {             "name" : "julie",             "age" : 32,             "gpa" : "3.4"         },         {             "name" : "heather",             "age" : 34,             "gpa" : "3.8"         }     ] }

i'd update both name , age fields simultaneously. here's i'm trying:

db.test.update(     {         'class':'english101',          'students.name':'julie'     },     {         $set: {             'students.$': {                 'name':'jules',                 'age':'31'             }          }      }  )

the result this:

{     "class" : "english101",     "students" : [         {             "name" : "jules",             "age" : "31",             # gpa gone!         },         {             "name" : "heather",             "age" : 34,             "gpa" : "3.8"         }     ] }

the problem instead of expected update , $set behavior replaces whole array item, instead of updating supplied fields.

how should doing this?

in case update object, overwrites everything. here correct approach. 

 db.test.update({       'class':'english101',        'students.name':'julie'  },{       $set: {           'students.$.name': 'jules',           'students.$.age' : 31       }  })

Comments

Post a Comment

Popular posts from this blog

python - Installing PyDev in eclipse is failed -

unable read repository @ http://pydev.sf.net/updates/content.xml. sun.security.validator.validatorexception: pkix path building failed: sun.security.provider.certpath.suncertpathbuilderexception: unable find valid certification path requested target i installing pydev in eclipse using python, doesn't install successfully. gives above error. happened? how solve error? i had error when trying install on laptop behind corporate firewall. couldn't tell setup of firewall, not sure of root cause. i got passed error installing pydev eclipse when out behind firewall. another way got around have eclipse on non-firewalled machine, install pydev eclipse, , copy whole eclipse directory non-firewalled machine firewalled machine. there better way, , way fix properly, didn't have time work out firewall doing. this on windows 7 machine (yeah know) not work *nix versions installed through package manager yum or apt.
Read more

PHP OOP-based login system -

lets building oop-based user authentication system, , incorporate following principles: direct injection, inheritance, encapsulation, polymorphism , single responsibility principle. my background in programming has relied on procedural programming, , thus, finding difficult put these practices correct use. assume have these classes: class config { public function set($key, $value); public function get($key, $default = null); } class user { public function __construct(pdo $dbh, $id = null); public function setprofile(profile $profile); } class auth { public function __construct(config $config); public function login($username, $password, $keeploggedin = true); public function isloggedin(); public function getloggedinuser(); public function logout(); public function register(array $data); } class session { public function start($sessionname = null); public function write($key, $value); public function read($key, $default =...
Read more

c# - Nested Internal Class with Readonly Hashtable throws Null ref exception.. on assignment -

in internal game class , have both a) defined nested internal gamertags class , b) defined gamertags[] _array variable. in internal gamertags class (the nested class, simplicity left out) have readonly hashtable . after initialization, still null ref exception when try assign value. i'm not changing pointer value only , need add initialization hastable? internal class gamertags { private readonly hashtable _privatereadonlyhashtable; private string _json; private string _hash; internal idictionary privatereadonlyhashtable { { return this._privatereadonlyhashtable; } } internal string hash { { this.ensurehash(); return this._hash; } } internal object this[string key] { { return this._privatereadonlyhashtable[k...
Read more