static void Main(string[] args)
{
//used v 2.4.3 of C# driver and v 3.4.1 of the db engine for this example
var client = new MongoClient();
IMongoDatabase db = client.GetDatabase("agg_example");
var collectionName = "points";
db.DropCollection(collectionName);
IMongoCollection<PlayerPoints> collection = db.GetCollection<PlayerPoints>(collectionName);
IEnumerable<PlayerPoints> data = GetDummyData();
collection.InsertMany(data);
//some seasons to filter by
var seasons = new[] {6, 7};
//clear out unparticipating players from aggregated data to reduce computation overhead
var seasonFilter = Builders<SeasonPoint>.Filter.In(season => season.Season, seasons);
var playerFilter = Builders<PlayerPoints>.Filter.ElemMatch(point => point.SeasonalPoints, seasonFilter);
//This shall remove all un-necessary seasons from aggregation pipeline
var bsonFilter = new BsonDocument { new BsonElement("SeasonalPoints.Season", new BsonDocument("$in", new BsonArray(seasons))) };
var groupBy = new BsonDocument// think of this as a grouping with an anonyous object declaration
{
new BsonElement("_id", "$_id"),//This denotes the key by which to group - in this case the player's id
new BsonElement("playerSum", new BsonDocument("$sum", "$SeasonalPoints.Point")),//We aggregate the player's points
new BsonElement("player", new BsonDocument("$first", "$$CURRENT")),// preserve player reference for projection stage
};
var sort = Builders<BsonDocument>.Sort.Descending(doc => doc["playerSum"]);
List<BsonDocument> a = collection
.Aggregate()
.Match(playerFilter)
.Unwind(x => x.SeasonalPoints)//this is where the magic happens
.Match(bsonFilter)
.Group(groupBy)
.Sort(sort)
.ToList();
static void Main(string[] args)
{
//used v 2.4.3 of C# driver and v 3.4.1 of the db engine for this example
var client = new MongoClient();
IMongoDatabase db = client.GetDatabase("agg_example");
var collectionName = "points";
db.DropCollection(collectionName);
IMongoCollection <BsonDocument> collection = db.GetCollection <BsonDocument>(collectionName);
IEnumerable <BsonDocument> data = GetDummyData().Select(d => d.ToBsonDocument());
collection.InsertMany(data);
//some seasons to filter by - note transformation to zero based
var seasons = new[] { 6, 7 };
//This is the query body:
var seasonIndex = seasons.Select(i => i - 1);
//This shall remove all un-necessary seasons from aggregation pipeline
var bsonFilter = new BsonDocument {
new BsonElement("Season", new BsonDocument("$in", new BsonArray(seasonIndex)))
};
var groupBy = new BsonDocument // think of this as a grouping with an anonyous object declaration
{
new BsonElement("_id", "$_id"), //This denotes the key by which to group - in this case the player's id
new BsonElement("playerSum", new BsonDocument("$sum", "$SeasonalPoints")), //We aggregate the player's points
new BsonElement("player", new BsonDocument("$first", "$$CURRENT")), // preserve player reference for projection stage
};
var sort = Builders <BsonDocument> .Sort.Descending(doc => doc["playerSum"]);
var unwindOptions = new AggregateUnwindOptions <BsonDocument>
{
IncludeArrayIndex = new StringFieldDefinition <BsonDocument>("Season")
};
var projection = Builders <BsonDocument> .Projection.Expression((doc => doc["player"]));
List <BsonValue> sorted = collection
.Aggregate()
.Unwind(x => x["SeasonalPoints"], unwindOptions)
.Match(bsonFilter)
.Group(groupBy)
.Sort(sort)
.Project(projection)
.ToList();
}
