Using Mongodb in .NET

http://docs.mongodb.org/manual/reference/sql-comparison/

public static string connectionString = "mongodb://localhost";
public static MongoClient Client = new MongoClient(connectionString);
public static MongoServer Server = Client.GetServer();
public static MongoDatabase MainDatabase = Server.GetDatabase("commerce");

[BsonIgnoreIfNull]
[BsonElement("esrb")]
public string ESRBAgeRating {
    get;
    set;
}
 
[BsonElement("format")]
public string Format {
    get;
    set;
}

BsonClassMap.RegisterClassMap<MongoProduct>(cm => {
    cm.AutoMap();
    cm.SetIgnoreExtraElements(true);
    cm.UnmapProperty(c => c.BuyItNowPrice);
    cm.GetMemberMap(c => c.Format).SetIgnoreIfNull(true);
    cm.GetMemberMap(c => c.Genre).SetIgnoreIfNull(true);
});

[BsonElement("listPrice")]
public int ListPriceInteger {
    get {
        return (int)(ListPrice * 10000); //4 dec places
    }
    set {
        ListPrice = value / 10000;
    }
}
 
//MSRP
[BsonIgnore]
public decimal ListPrice {
    get;
    set;
}

BsonClassMap.RegisterClassMap<Dimension>(cm => {
    cm.AutoMap();
    cm.GetMemberMap(c => c.Height).SetSerializer(new DecimalSerializer())
        .SetElementName("height");
    cm.GetMemberMap(c => c.Length).SetSerializer(new DecimalSerializer())
        .SetElementName("length");
    cm.GetMemberMap(c => c.Weight).SetSerializer(new DecimalSerializer())
        .SetElementName("weight");
    cm.GetMemberMap(c => c.Width).SetSerializer(new DecimalSerializer())
        .SetElementName("width");
});

public class Dimension {
 
    public decimal Length {
        get; set;
    }
 
    public decimal Height {
        get; set;
    }
 
    public decimal Width {
        get; set;
    }
 
    public decimal Weight {
        get; set;
    }
}

• http://docs.mongodb.org/ecosystem/tutorial/serialize-documents-with-the-csharp-driver/
  
• http://docs.mongodb.org/ecosystem/tutorial/use-csharp-driver/
  

var query = Query<MongoProduct>
    .Where(item => item.ASIN == asinName);
 
var asin = Collections.ProductCollection.FindOne(query);

var query = Query<MongoProduct>
    .Where(item => item.PackageDimensions.Weight < .1m);
var itemsVeryLight = Collections.ProductCollection
    .FindAs<MongoProduct>(query).ToList();

//does work
var asin2 = Collections.ProductCollection.Find(query)
    .SetFields(Fields.Include("listPrice", "title")).FirstOrDefault();
//does not work
var asin2a = Collections.ProductCollection.Find(query)
    .SetFields(Fields.Include("ListPriceInteger", "Title")).FirstOrDefault();
 
//must be the c# class properties.
var asin3 = Collections.ProductCollection.Find(query)
    .SetFields(Fields<MongoProduct>.Include(c => c.ListPriceInteger, c => c.Title)).FirstOrDefault();

var product = new MongoProduct() { };
 
Collections.ProductCollection.Insert<MongoProduct>(product);

var product = new MongoProduct() { };
 
Collections.ProductCollection.Save<MongoProduct>(product);

Collections.ProductCollection.InsertBatch<Product>(list);

• There is no concept of a pessimistic lock
  
• Atomic updates are per document
• Reading, modifying the document and saving is not atomic
• Transactions do not exist

• A Query (optional)
  
• A Sort operator (optional)
  
• If the document should be removed
  
• The Update Statement
  
• If you want the new document returned
  
• The fields to return (optional)
  
• If an upsert should be performed
  
• The values to push if the item is new (optional)
  

var asinName = "B00000J1TX";
var query = Query.And(Query.EQ("_id", asinName));
var sortBy = SortBy.Null;
var update = Update.Inc("counter", 1).Set("lastView", DateTime.Now)
    .SetOnInsert("keywords", new BsonArray(new[] { "new" }));
var result = Collections.ProductViewCollection
    .FindAndModify(query, sortBy, update, true, true);
 
var found = Collections.ProductViewCollection.FindOne(query);

• findAndModify will only update one record, no matter how you use it.
  
• If multiple documents need to be updated, you must use the Update method.
  
• Each document update will be atomic but the update as a whole will not
• If there is a failure while performing your update, there is no way to know which documents were updated and which ones were not.

var update = Update.Inc("counter", 1);
var result = Collections.ProductViewCollection
    .Update(null, update); 

var array = new List<string>() { "new" };
var query = Query<MongoProductView>.All(item => item.Keywords, array);
//show that we did return a product.
var found = Collections.ProductViewCollection.Find(query).ToList();
//Add keyword to all documents that have a keyword of new
var update = Update.AddToSet("keywords", "test");
//you could also use push if you wanted it added no matter what.
//var update = Update.Push("keywords", "test");
Collections.ProductViewCollection.Update(query, update);
 

• Foreign Keys do not exist in MongoDB
  
• You may use References or store the data in the document
  
• Depending on how often you need to display or work with those values will dictate if you have denormalized data

var update = Update.Set("extra", "");
var result = Collections.ProductViewCollection
    .Update(null, update);

var update = Update.Unset("extra");
var result = Collections.ProductViewCollection
    .Update(null, update);

Collections.ProductViewCollection.EnsureIndex(IndexKeys<MongoProductView>
    .Ascending(item => item.Counter), IndexOptions.SetBackground(true));

Collections.ProductViewCollection.Drop();

Collections.ProductCollection.FindAll();

Collections.ProductCollection.Find(query)
    .SetSortOrder(SortBy<MongoProduct>.Ascending(item => item.Title));

var query = Query<MongoProduct>.Where(item => item.ListPrice < 4.99m);
var count = Collections.ProductCollection.Count(query);

Collections.ProductCollection.Distinct("Title", query);

• MongoDB has built in functionality to perform Map Reduce
  
• It is much easier to get up and running than Hadoop
  
• Can be used as a connector for Hadoop
  

• "Like" Statements are very slow
  
• Full Text search can only exist for one field per collection
  
• If a value changes on a denormalized field, you must perform an update statement to keep the values in sync
• Update statements are not intuitive
• No transactions across multiple rows (documents)
• Two phase commits difficult to understand and keeping state for a rollback is even more difficult

• ElasticSearch is an option and is free
  
• Requires MongoDB be set up as a Replica Set
  

• It is possible and allows for massive scale out but you need a coordinator
  
• Additional reading can be found at