javascript - how to update an array inside a MongoDB collection with another array but update only changed values? -

having following collection named eshops:

{ "_id" : objectid("53e87e239ae974e6a0a81004"), "name" : "www.example.com", "products" : [     {         "name" : "apple", //lets name key here primary key of products         "status" : 0     },     {         "name" : "banana",         "status" : 0     },     {         "name" : "iphone",         "status" : 0     } ] } 

and having array

var products = [ {name: "apple", status: 1} {name: "notebook", status: 0} ] 

what should update query if wanted following result?

{ "_id" : objectid("53e87e239ae974e6a0a81004"), "name" : "www.example.com", "products" : [     {         "name" : "apple",         "status" : 1     },     {         "name" : "banana",         "status" : 0     },     {         "name" : "iphone",         "status" : 0     },     {         "name" : "notebook",         "status" : 0     } ] } 

the full explaination of @ end read on.

that cannot cannot done "atomically" in single operation , best "bulk" operations best way it.

var products = [     {name: "apple", status: 1}     {name: "notebook", status: 0} ];  var bulk = db.collection.initializeorderedbulkop();  products.foreach(function(product) {      // try update     bulk.find({          "_id" : objectid("53e87e239ae974e6a0a81004"),         "products.name": product.name     })     .updateone({         "$set": { "products.$.status": product.status }     });      // try "push"     bulk.find({          "_id" : objectid("53e87e239ae974e6a0a81004"),         "products.name": { "$ne": product.name }     })     .updateone({         "$push": { "products": product }     });  }); bulk.execute(); 

the other alternative retrieve document via .findone() or similar operation, alter array content in client code , .save() altered content back.

that don't want since there no guarantee document has not "changed" since read memory. , if other members added array sort of action "overwrite" them.

so loop items multiple updates. @ least "bulk" operations send these @ once server without waiting responses individual writes.

but point out. if value still same? need @ "writeresult" response "bulk" operation on .execute():

writeresult({ "nmatched" : 2, "nupserted" : 0, "nmodified" : 2 }) 

so there 2 (2) actions here depite 4 (4) operations being sent in total. if array contained 1 more item, "iphone" without changes:

var products = [     {name: "apple", status: 1}     {name: "notebook", status: 0},     {name: "iphone", status: 0 } ]; 

then response this:

writeresult({ "nmatched" : 3, "nupserted" : 0, "nmodified" : 2 }) 

since "bulk" api smart enough see value "status" on matching "iphone" not different value present ( assuming nothing else changed in between ) , not report modification.

so let server work, because smarts code there.