MongoDB.Driver是操作mongo数据库得驱动,最近2.0以下版本已经从GitHub和Nuget中移除了,也就是说.NET Framework4.0不再能从官方获取到MongoDB得驱动了,其次MongoDB.Driver2.0开始API变更巨大,本文不适用MongoDB.Driver2.0以下版本,亦不适用.NET Framework4.5以下版本
要在.NET中使用MongoDB,就必须引用MongoDB的驱动,使用Nuget安装MongoDB.Driver是最方便得,目前Nuget支持的MongoDB程序包有对.NET Framework4.5以上版本的依赖
安装完成之后会在引用中新增三个MongoDB得程序集引用,其中MongoDB.Driver.Core在2.0版本以下是没有得
先构建一个实体基类,因为Mongo要求每个文档都有唯一Id,默认为ObjectId类型(根据时间Mac地址Pid算出来的,类似GUID,适用于分布式),在这个基类中添加Id属性
using MongoDB.Bson; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace MongoTest { /// <summary> /// 自定义类型Id /// </summary> /// <typeparam name="T"></typeparam> public abstract class BaseEntity<T> { public T Id { get; set; } } /// <summary> /// Mongo默认填充ObjectId类型的Id /// </summary> public abstract class DefaultIdEntity : BaseEntity<ObjectId> { } }
开始构建数据库访问类DbContext
using MongoDB.Driver; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace MongoTest { public class DbContext { public readonly IMongoDatabase _db; public DbContext() { //此为开启验证模式 必需使用用户名 密码 及指定登陆的数据库 可采用,分割连接多个数据库 var client = new MongoClient("mongodb://root:[email protected]:27017/admin"); //未开启验证模式数据库连接 // var client = new MongoClient("mongodb://127.0.0.1:27017"); //指定要操作的数据库 _db = client.GetDatabase("mytest"); } private static string InferCollectionNameFrom<T>() { var type = typeof(T); return type.Name; } public IMongoCollection<T> Collection<T, TId>() where T : BaseEntity<TId> { var collectionName = InferCollectionNameFrom<T>(); return _db.GetCollection<T>(collectionName); } /// <summary> /// 实体类名和数据库中文档(关系型数据库中的表)名一致时使用 /// </summary> public IMongoCollection<T> Collection<T>() where T : DefaultIdEntity { var collectionName = InferCollectionNameFrom<T>(); return _db.GetCollection<T>(collectionName); } public IMongoCollection<T> Collection<T, TId>(string collectionName) where T : BaseEntity<TId> { return _db.GetCollection<T>(collectionName); } /// <summary> /// 实体类名和数据库中文档(关系型数据库中的表)不一致时使用,通过collectionName指定要操作得文档 /// </summary> public IMongoCollection<T> Collection<T>(string collectionName) where T : DefaultIdEntity { return _db.GetCollection<T>(collectionName); } } }
现有数据库数据 文档book 包含数据如下
开始构建与文档对应得实体,mongo是文档数据库,的单词得大小写是敏感得,所以构建得实体的字段也应该是小写得,有点不符合习惯
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace MongoTest { public class book : DefaultIdEntity { public string title { get; set; } public double price { get; set; } public string author { get; set; } public string publisher { get; set; } public int saleCount { get; set; } } }
现在开始增删查改操作,其中查找和删除得filter有两种形势,lambda和Definition
using MongoDB.Driver; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace MongoTest { public class OperatDb { static IMongoCollection<book> bookDao; static OperatDb() { bookDao = new DbContext().Collection<book>(); } public static void Excute() { Console.WriteLine(); QueryAll(); Console.WriteLine(); Query(); Console.WriteLine(); Insert(); Console.WriteLine(); QueryAll(); Console.WriteLine(); Update(); Console.WriteLine(); Delete(); Console.WriteLine(); QueryAll(); Console.ReadKey(); } public static void QueryAll() { var books = bookDao.Find(x => true).ToList(); foreach (var item in books) { Console.WriteLine(item.ToString()); } } public static void Query(System.Linq.Expressions.Expression<Func<book, bool>> filter = null) { if (filter == null) filter = x => x.author == "韩寒"; var books = bookDao.Find(filter).ToList(); foreach (var item in books) { Console.WriteLine(item.ToString()); } } public static void Update() { var filter = Builders<book>.Filter.Eq(x => x.title, "悲伤逆流成河"); var book = bookDao.Find(filter).FirstOrDefault(); Console.WriteLine("更新前:{0}", book.ToString()); var update = Builders<book>.Update.Set(x => x.publisher, "新时代出版社") .Set(x => x.price, 35) .Inc(x => x.saleCount, 10); var result = bookDao.UpdateOne(filter, update); Console.WriteLine("IsAcknowledged:{0} MatchedCount:{1} UpsertedId:{2} IsModifiedCountAvailable:{3} ModifiedCount:{4}", result.IsAcknowledged, result.MatchedCount, result.UpsertedId, result.IsModifiedCountAvailable, result.ModifiedCount); book = bookDao.Find(filter).FirstOrDefault(); Console.WriteLine("更新后:{0}", book.ToString()); } public static void Delete() { var result = bookDao.DeleteOne(x => x.title == "悲伤逆流成河"); Console.WriteLine("DeletedCount:{0} IsAcknowledged:{1} ", result.DeletedCount, result.IsAcknowledged); } public static void Insert() { var bookInfo = new book { Id = new MongoDB.Bson.ObjectId(), author = "郭敬明", price = 10.00, publisher = "春风文艺出版社", saleCount = 0, title = "悲伤逆流成河" }; bookDao.InsertOne(bookInfo); } } }
因为我对book类的ToString方法,所以输出结果如下
上面都是用的数据库和实体字段名一致的情况,如果不一致怎么办呢,Xml和Json等序列化都有标签特性可以用别名,Bson肯定也会有,新建BookInfo实体如下
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace MongoTest { public class BookInfo : DefaultIdEntity { public string Title { get; set; } public double Price { get; set; } public string Author { get; set; } public string Publisher { get; set; } public int SaleCount { get; set; } } }
将上面执行操作的book全部替换成BookInfo试试,发现没报错,再去数据库看看会发现,数据库新增了一个文档,我们预期得结果是要操作在book上,显然这不是我们想要得
现在将调用Collection调用改为指定collectionName为book的形式
static IMongoCollection<BookInfo> bookDao; static OperatDb() { bookDao = new DbContext().Collection<BookInfo>("book"); }
再次运行程序,发现报错了,文档节点和实体字段不匹配
现在给BookInfo得字段都加上Bson的标签特性
using MongoDB.Bson.Serialization.Attributes; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace MongoTest { public class BookInfo : DefaultIdEntity { [BsonElement("title")] public string Title { get; set; } [BsonElement("price")] public double Price { get; set; } [BsonElement("author")] public string Author { get; set; } [BsonElement("publisher")] public string Publisher { get; set; } [BsonElement("saleCount")] public int SaleCount { get; set; } } }
现在一切正常了,显示结果和之前得一样就不再贴图了,有子文档得数据操作与此类似,譬如有如下数据
构建实体如下
public class Director : Entity { [BsonElement("name")] public string Name { get; set; } [BsonElement("country")] public string Country { get; set; } [BsonElement("age")] public int Age { get; set; } [BsonElement("movies")] public List<Movie> Movies { get; set; } } public class Movie { [BsonElement("name")] public string Name { get; set; } [BsonElement("year")] public int Year { get; set; } }