MongoDb

use company

company> db.employee.insertOne({_id:1,employee_name:"Raman",employee_address:1})
{ acknowledged: true, insertedId: 1 }
company> db.employee.insertOne({_id:2,employee_name:"kamal",employee_address:2})
{ acknowledged: true, insertedId: 2 }
company> db.employee.insertOne({_id:3,employee_name:"sameer",employee_address:1})
{ acknowledged: true, insertedId: 3 }

company> db.address.insertOne({_id:1,zone:'north_zone',street:'hudda market, sector-21',state:'Haryana'})
{ acknowledged: true, insertedId: 1 }
company> db.address.insertOne({_id:2,zone:'south_zone',street:'Khan market, sector-51',state:'Madras'})
{ acknowledged: true, insertedId: 2 }
company>

company> show collections
address
employee
employer
company> db.employee.find()
[
  { _id: 1, employee_name: 'Raman', employee_address: 1 },
  { _id: 2, employee_name: 'kamal', employee_address: 2 },
  { _id: 3, employee_name: 'sameer', employee_address: 1 }
]
company> db.address.find()
[
  {
    _id: 1,
    zone: 'north_zone',
    street: 'hudda market, sector-21',
    state: 'Haryana'
  },
  {
    _id: 2,
    zone: 'south_zone',
    street: 'Khan market, sector-51',
    state: 'Madras'
  }
]
company>

company> db.employee.aggregate([{$lookup:{from:"address",localField:'employee_address',foreignField:'_id',as:'Address Detals'}}])
[
  {
    _id: 1,
    employee_name: 'Raman',
    employee_address: 1,
    'Address Detals': [
      {
        _id: 1,
        zone: 'north_zone',
        street: 'hudda market, sector-21',
        state: 'Haryana'
      }
    ]
  },
  {
    _id: 2,
    employee_name: 'kamal',
    employee_address: 2,
    'Address Detals': [
      {
        _id: 2,
        zone: 'south_zone',
        street: 'Khan market, sector-51',
        state: 'Madras'
      }
    ]
  },
  {
    _id: 3,
    employee_name: 'sameer',
    employee_address: 1,
    'Address Detals': [
      {
        _id: 1,
        zone: 'north_zone',
        street: 'hudda market, sector-21',
        state: 'Haryana'
      }
    ]
  }
]