Mongodb Update Many

Question

I am developing using express js and npm module mongodb with mongodb as database. I have two collections namely \"users\" and \"activities\". There can be 1000s of activities of

Answer 1

1. This is typical one-to-many relationship. So in case of the User you can have the following schema:

//User
{
  //_id: ObjectId - this one is unique and inserted to every document by default  
  profile: String,
    ...
}
  
//Activity
{
  description: String,
  ...,

  userId: String, // referecing the user _id, e.g. "56a5eccb2258799919dc2c40"
}
  

2. If you want to update many docs for activity:

db.activities.update({ userId: '56a5eccb2258799919dc2c40' }, { 
    $set: {
      description: 'new description'
    } 
  },
  {
    multi: true //means update all matching docs
  });

              

Answer 2

You should store just the _id of the User in the Activity. Then use that to access the User via the Activity (if that's what you want to do).