MongoDB代码实例

增加用户余额

var client = new MongoClient("mongodb://192.168.11.137:27019");

            var session = client.StartSession();
            session.StartTransaction();


            var database = client.GetDatabase("MyTestDB2");
            var collection = database.GetCollection<UserInfo>("UserInfo");


            var update = new UpdateDefinitionBuilder<UserInfo>()
                .Inc(m => m.Balance, 100);//余额增加100

            var option = new FindOneAndUpdateOptions<UserInfo, UserInfo>();
            option.ReturnDocument = ReturnDocument.After;//返回更新后对象try
                {
                    var dataitem = collection.FindOneAndUpdate<UserInfo>(session, m => m.Name == "JackTan", update, option);
                    
                }
                catch (MongoCommandException ex)
                {
                    //if (ex.Code == 112)  其他事务正在修改这个文档
                    
                    throw;
                }
            
           

            session.CommitTransaction();

创建索引

var database = client.GetDatabase("MyTestDB2");
            var collection = database.GetCollection<UserInfo>("UserInfo");

 
           
            var indexModel = new CreateIndexModel<UserInfo>(
               Builders<UserInfo>.IndexKeys.Ascending(_ => _.Name), new CreateIndexOptions
               {
                   Name = "UerInfo_index_name",                   Unique = true,  //唯一值索引
               });
            var indexname = collection.Indexes.CreateOne(indexModel);
collection.Indexes.CreateOne( Builders<UserInfo>.IndexKeys.Hashed(m=>m.Id)); //设置Id为哈希类型，并建立索引，哈希类型是否以后分片集群做准备的

注意：索引的创建不受事务控制

查询现有索引：

collection.Indexes.List().ToList();

如何判断插入重复的数据（违法唯一值索引）

var database = client.GetDatabase("MyTestDB2");
            var collection = database.GetCollection<UserInfo>("UserInfo");
            try
            {
                collection.InsertOne(new UserInfo
                {
                    Name = "JackTan"
                });
            }
            catch (MongoWriteException ex)
            {
                if(ex.WriteError.Category == ServerErrorCategory.DuplicateKey)
                {
                    //插入重复数据
                }
                throw;
            }

MongoDB监控查询命令、linq联合查询

            // 创建 MongoClientSettings 对象
            var settings = MongoClientSettings.FromConnectionString("mongodb://192.168.11.137:27017");


            // 将 CommandLogger 设置为 MongoClientSettings 的 CommandLogger 属性
            settings.ClusterConfigurator = cb => {
                cb.Subscribe<CommandStartedEvent>(e =>
                {
                   var cmd = e.Command.ToString();
                });
            };

            var client = new MongoClient(settings);

            var database = client.GetDatabase("MyTestDB");
            var userinfos = database.GetCollection<UserInfo>("UserInfo").AsQueryable();
 
            var ages = database.GetCollection<UserAge>("UserAges").AsQueryable();
            var ageinfos = database.GetCollection<AgeInfo>("AgeInfos").AsQueryable();

            var user = (from m in userinfos
                         join a in ages on m.Id equals a.UserId into aGroup
                        from a2 in aGroup.DefaultIfEmpty()
                        join b in ageinfos on a2.Id equals b.AgeId into  bGroup
                        from b2 in bGroup.DefaultIfEmpty()
                        select new
                        {
                            Name = m.Name,
                            Time = b2.CreateTime,
                            Age = a2.Age
                        }).FirstOrDefault();