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       }  })