[{"Empname":"Doug","Group":[{"Category":[{"Categoryid":123,"Categoryname":"science"},{"Categoryid":233,"Categoryname":"Maths"}]}]},{"Empname":"stark","Group":[{"Category":[{"Categoryid":123,"Categoryname":"science"},{"Categoryid":144,"Categoryname":"language "}]}]}]

db.collection.update({},{$set:{"Group.$[].Category.$[category].CategoryLabel":"Hex","Group.$[].Category.$[category].CategoryCode":"Hex-D"}},{arrayFilters:[{"category.Categoryid":123,"category.Categoryname":"science"}],multi:true})