使用MongoDB的支援Linq 驅動NoRM

MongoDB的驅動有好幾個，分布式檔案儲存體的資料庫開源項目MongoDB裡使用的是github.com/samus/mongodb-csharp，monogodb-csharp不是強型別，使用起來不方便。轉向使用支援強型別訪問MongoDB的NoRM C# driver。NoRM 驅動和MongoDB-CSharp的一個區別的地方就是NoRM使用強型別的類操作MongoDB-CSharp的Document類。

使用NoRM很簡單，引用NoRM.dll就可以了，下面的例子是一個控制台程式：

模型類，代表儲存到資料庫的資料

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Norm;

namespace FirstMongoDb
{
    public class Customer: IHaveIdentifier
    {
        public ObjectId _id { get; set; }
        public string Name { get; set; }
        public DateTime LastOrderUtc { get; set; }
        public List<string> OrderedItems { get; set; }

        public Customer()
        {
            OrderedItems = new List<string>();
        }
    }
}

這個足夠簡單了，下面我們連到資料庫

public class MongoDbDataContext : IDisposable
    {
        private readonly MongoQueryProvider provider;

        public MongoQueryProvider Provider
        {
            get { return provider; }
        }

        public static string DatabaseName { get; set; }

        public MongoDbDataContext()
        {
            if ( string.IsNullOrEmpty( DatabaseName ) )
            {
                throw new InvalidOperationException( "You must set the static DatabaseName property." );
            }
            provider = new MongoQueryProvider(
                new Mongo( DatabaseName, "127.0.0.1", "27017", null ) );
        }

使用NoRM去冬串連到資料需要提供一個資料庫名，伺服器位址和連接埠，參看上述紅色代碼。

插入一個對象到資料庫

private static void Insert()
        {

            Customer c = new Customer();
            c.Name = "Jake";
            c.LastOrderUtc = DateTime.UtcNow;
            c.OrderedItems.Add("frappa");
            c.OrderedItems.Add( "beer" );
            c.OrderedItems.Add( "redbull!" );
            c.OrderedItems.Add( "wings" );

            using ( MongoDbDataContext ctx = new MongoDbDataContext() )
            {
                ctx.Add(c);
            }
        }

使用LINQ查詢資料庫

using ( MongoDbDataContext ctx = new MongoDbDataContext() )
{
                var query =
                    from c in ctx.Customers
                    where c.Name == "Michael"
                    orderby c.LastOrderUtc descending
                    select c;

                foreach (var customer in query)
                {
                    Console.WriteLine("{0} bought {1}",
                        customer.Name,
                        customer.OrderedItems.FirstOrDefault()
                        );
                }
            }

 

參考：Using MongoDB with the NoRM driver