Database
[{"devices":["1","2"],"eui":"A5AC840871F01D65","key":"5BCBF770D2B43638860F7DA3733ED1B3",},{"devices":["3","4"],"eui":"A5AC840871F01D65","key":"5BCBF770D2B43638860F7DA3733ED1B3",}]
Query
db.collection.update({devices:"1"},{$pull:{devices:"1"}})