MongoDB Data Access 基类

最新推荐文章于 2025-09-06 09:33:29 发布

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原文链接：http://www.cnblogs.com/fulijun/archive/2013/06/12/3132563.html

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#数据库

本文介绍了一个用于MongoDB操作的基类，该类封装了常见的CRUD操作及分页功能。通过继承此基类并实现数据库名称和集合名称的方法，可以方便地进行数据增删改查等操作。

该类封装了 MongoDB的一些常用操作，使用只需要从该类继承，并实现GetDataBaseName() 获取数据库名称方法和 GetCollectionName（）获取集合名称，即可实现MongoDB的CRUD操作，该基类带一个MongoDB 分页方法。

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MongoDB.Driver;
using MongoDB.Bson;
using MongoDB.Driver.Builders;

namespace sc.MongoDBDataAccess
{
    public abstract class BaseMgDAL<T>
    {
        static readonly string connectionString = System.Configuration.ConfigurationManager.AppSettings["MongoDBConn"];   //string.Empty ;// "mongodb://localhost";
        static MongoClient client = null;
        static protected MongoServer server = null;

        protected MongoDatabase database = null;//子类的数据库
        protected MongoCollection<T> collection = null;//子类的集合

        static SortByDocument DEF_SORT_ASC = new SortByDocument("_id", 1);
        static SortByDocument DEF_SORT_DESC = new SortByDocument("_id", -1);

        //////////////////////////////////split line///////////////////////////////

        /// <summary>
        /// 静态构造函数
        /// </summary>
        static BaseMgDAL()
        {
            client = new MongoClient(connectionString);
            server = client.GetServer();
        }

        /// <summary>
        /// 构造函数
        /// </summary>
        public BaseMgDAL()
        {
            database = server.GetDatabase(GetDataBaseName());
            collection = database.GetCollection<T>(GetCollectionName());
        }
        
        /// <summary>
        /// 插入一个项目
        /// </summary>
        /// <param name="obj">要插入的项目</param>
        /// <returns>返回该对象</returns>
        public T Insert(T obj)
        {
            collection.Insert(obj);
            return obj;
        }

        /// <summary>
        /// 更新一条数据
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public bool Update(T obj)
        {
            try
            {
                collection.Save(obj);
                return true;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        /// <summary>
        /// 删除一条数据
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public bool Delete(ObjectId id)
        {
            try
            {
                var querry = Query.EQ("_id", id);
                collection.Remove(querry);
                return true;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        /// <summary>
        /// 根据ObjectId获取数据
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public T GetByID(ObjectId id)
        {
            var query = Query.EQ("_id", id);
            var result = collection.FindOne(query);
            return result;
        }

        /// <summary>
        /// 返回分页结果
        /// </summary>
        /// <param name="query">查询条件</param>
        /// <param name="collection">集合</param>
        /// <param name="startIndex">开始序号</param>
        /// <param name="endIndex">结束序号</param>
        /// <returns>查询的结果集</returns>
        public MongoCursor<T> MongoDBPage(IMongoQuery mongoQuery, MongoCollection<T> collection, long startIndex, long endIndex)
        {
            if (startIndex < 0 || endIndex < 0)
                throw new ArgumentException("索引必须从零开始，且不能小于零");

            long maxSize = MongoDBCount(mongoQuery, collection);//查询总数据

            if (startIndex > maxSize)
                return null;

            //获取要返回的数据大小
            long selectSize = startIndex + endIndex;
            if (selectSize > maxSize)
                selectSize = maxSize;
            long returnSize = selectSize - startIndex;

            return collection.Find(mongoQuery).SetSortOrder(DEF_SORT_ASC)
                 .SetLimit((int)selectSize)
                 .SetSortOrder(DEF_SORT_DESC)
                 .SetLimit((int)returnSize)
                 .SetSortOrder(DEF_SORT_ASC);
        }

        /// <summary>
        /// 获取结果集大小
        /// </summary>
        /// <param name="query">查询条件</param>
        /// <param name="collection">MongoDB集合</param>
        /// <returns></returns>
        public long MongoDBCount(IMongoQuery mongoQuery, MongoCollection<T> collection)
        {
            return collection.Find(mongoQuery).Count();
        }

        public abstract string GetDataBaseName();
        public abstract string GetCollectionName();
    }
}