mongoDB Many-to-Many Data Modeling

GroupDocuments.js

db.groups.insert({
  "_id": ObjectId("4e54ed9f48dc5922c0094a42"),
  "groupName": "mongoDB User",
  "persons": [
    ObjectId("4e54ed9f48dc5922c0094a43"),
    ObjectId("4e54ed9f48dc5922c0094a40")
  ]
});

db.groups.insert({
  "_id": ObjectId("4e54ed9f48dc5922c0094a41"),
  "groupName": "mongoDB Administrator",
  "persons": [
    ObjectId("4e54ed9f48dc5922c0094a43")
  ]
});

Indexes.js

db.person.ensureIndex({"groups": 1});

db.groups.ensureIndex({"persons": 1});

PersonDocuments.js

db.person.insert({
  "_id": ObjectId("4e54ed9f48dc5922c0094a43"),
  "firstName": "Joe",
  "lastName": "Mongo",
  "groups": [
    ObjectId("4e54ed9f48dc5922c0094a42"),
    ObjectId("4e54ed9f48dc5922c0094a41")
  ]
});

db.person.insert({
  "_id": ObjectId("4e54ed9f48dc5922c0094a40"),
  "firstName": "Sally",
  "lastName": "Mongo",
  "groups": [
    ObjectId("4e54ed9f48dc5922c0094a42")
  ]
});

Queries.js

// Get all persons in the "mongoDB User" group
db.person.find({"groups": ObjectId("4e54ed9f48dc5922c0094a42")});

// Get all persons in the "mongoDB Administrator" group
db.person.find({"groups": ObjectId("4e54ed9f48dc5922c0094a41")});

// Get all groups for "Joe Mongo"
db.groups.find({"persons": ObjectId("4e54ed9f48dc5922c0094a43")});

// Get all groups for "Sally Mongo"
db.groups.find({"persons": ObjectId("4e54ed9f48dc5922c0094a40")});