受欢迎的博客标签

Mongodb c# .net driver lookup,GroupJoin

Published

GroupJoin

public class Entity
{
  public ObjectId id;
  public string name { get; set; }
}

 

var query = entities.AsQueryable()
    .Where(p => listNames.Contains(p.name))
    .GroupJoin(
      others.AsQueryable(),
      p => p.id,
      o => o.entity,
      (p, o) => new { p.id, p.name, other = o.First() }
    )
    .OrderByDescending(p => p.other.name);

Mongo db c# driver - how to join by id in collection?

Class A
{
   public string id;
   public string name;
   public list<string> classBReferenceid; // <--- I want use this as the "keys" for the join
   public list<B> myBs;
}
Class B
{
   public string id; // <--- I use this as the "key" for the join
   public string name;
}

 

IMongoCollection<A> mongoACollection = // already set in driver....
IMongoCollection<B> mongoBCollection = // already set in driver....

IAggregateFluent<A> results = _mongoACollection.Aggregate().
                Lookup<A, B, A>(
                    mongoBCollection,
                    a => a.classBReferenceid,
                    b => b.Id,
                    a => a.myBs);

 

Querying an Untyped Object Inside MongoDB

https://dzone.com/articles/querying-untyped-object-inside