Handling a one-to-many relationship MongoDB schema design - mongodb

Question

I am currently designing the MongoDB schema for an event management system. The ER diagram is as follows:
The concept is fairly simple:
A company can create 1 or more events (estimating x500s of companies)
A client can attend 1 or more events from a multitude of companies (estimating x200 per client..also estimate x1000s of clients)
The is the classic many-to-many relationship, right?
Now I come from an RDBMS background, so my instincts on structuring a MongoDB schema might be incorrect. However I like MongoDB's flexible document nature and so I tried to come up with the following model structure:
Company model
{
_id: <CompanyID1>,
name: "Foo Bar",
events: [<EventID1>, <EventID2>, ...]
}
Event model
{ _id: <EventID1>,
name: "Rockestra",
location: LocationSchema, // (model below)
eventDate: "01/01/2019",
clients: [<ClientID1>, <ClientID2>, ...]
}
Client model
{ _id: <ClientID1>,
name: "Joe Borg"
}
Location model
{ _id: <LocationID1>,
name: "London, UK"
}
My typical query scenarios would probably be:
List all events organised by a specific company (including location details)
List all registered clients for a particular event
Would this design and approach be a sensible one to use given the cardinality I stated above? I guess one of the pitfalls of this design is that I could not get the company details if I just query the events model.

Answer 1

I would do
Company model
{
_id: <CompanyID1>,
name: "Foo Bar"
}
Event model
{ _id: <EventID1>,
name: "Rockestra",
location: LocationSchema, // embedded, not a reference
eventDate: "01/01/2019",
company: <CompanyID1> // indexed reference.
}
Client model
{ _id: <ClientID1>,
name: "Joe Borg",
events: [<EventID1>, <EventID2>, ...] // with index on events
}
List all events organised by a specific company (including location details):
db.events.find({company:<CompanyID1>})
List all registered clients for a particular event:
db.clients.find({events:<EventID1>})

Answer 2

It's not many-to-many unless a single event can be created by many companies. It looks like you are describing one-to-many.
This is the way I'd approach it.
Company model
{
_id:
name:
}
Client model
{
_id:
name:
}
ClientEvents model
{
_id
clientId
eventId
}
Event model
{
_id:
companyId:
name:
locationId:
eventDate:
}
Location model
{
_id:
name: "London, UK"
}