我的基于asp.net mvc5 +mysql+dapper+easyui 的Web开发框架（1）数据库访问（0）

一、数据库访问 概述

　　1. 数据库使用mysql，orm采用dapper框架。dapper框架应用简单，只是需要自己手写sql语句，但是对于像我这样写了多年sql语句的人来说，这应该不算问题，个人还是比较喜欢这种手写sql语句的框架。

　　Dapper 虽然已经非常简单，但是为了调用时方便还是进行了一下封装 ，这样在写DAL 层方法时，就不用每次都try catch了。

　　2.先放代码：

　　调用方法示例：

        #region role  增删改查
        /// <summary>
        /// 增加一条
        /// </summary>
        public static void AddRole(Role role, IDbTransaction tran = null)
        {
            string sql = @"insert into role(Id,Name,Note)
                       values(@Id,@Name,@Note)";
            role.EnsureIdNotNull();
            DB.DBHelper.Execute(sql, role, tran);
        }

        /// <summary>
        /// 更新 
        /// </summary>
        public static void UpdateRole(Role role, IDbTransaction tran = null)
        {
            string sql = @"update role set Name=@Name,Note=@Note where Id=@Id";
            DB.DBHelper.Execute(sql, role, tran);
        }

        /// <summary>
        /// 删除 一条记录
        /// </summary>
        public static void DeleteRole(string Id, IDbTransaction tran = null)
        {
            string sql = "select count(1) from userrole where RoleId= @Id";
            var c = DB.DBHelper.ExecuteScalar<int>(sql, new { Id = @Id });
            if (c > 0)
            {
                throw new OperateException("该角色已经有用户在使用，不能删除");
            }

            List<string> sqllist = new List<string>();
            sqllist.Add("delete from role where Id=@Id");
            sqllist.Add("delete from rolemenu where RoleId=@Id"); //同步删除为角色分配的权限
            DB.DBHelper.Execute(sqllist, new { Id = Id }, tran);
        }

        /// <summary>
        /// 列表查询
        /// </summary>
        /// <param name="pl"></param>
        /// <returns></returns>
        public static ResultSet<Role> GetRoleList(ParamList pl)
        {
            string sql = @"select  Id,Name,Note from role where 1=1";
            pl.orderby = "Name";
            //添加各种查询条件
            if (pl.isnotnull("keywords"))
            {
                sql += " and instr(concat(Name,Note),@keywords)>0";
            }
            return DB.DBHelper.GetResultSet<Role>(sql, pl.orderby, pl);
        }
        #endregion

DBHelper 类:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using System.Data;
using Dapper;
using CommonModel;

namespace DBTools
{
    /// <summary>
    /// 执行sql ，抛出异常
    /// </summary>
    public class DBHelper
    {
        #region 连接信息
        public virtual string ConnectionString
        {
            get;
            set;
        }
        public virtual DataBaseType DBType
        {
            get;
            set;
        }
        #endregion

        #region 获取DBAdapter
        public DBAdapter GetDBAdapter()
        {
            return DBTools.DBFactory.GetAdapter(DBType, ConnectionString);
        }

        #endregion

        #region 查询
        public List<dynamic> Query(string sql, object query = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                var m = conn.Query(sql, query).ToList();
                return m;
            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }

        public List<T> Query<T>(string sql, object query = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                var m = conn.Query<T>(sql, query).ToList<T>();
                return m;
            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }

        public T ExecuteScalar<T>(string sql, object query = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                var m = conn.ExecuteScalar<T>(sql, query, tran);
                return m;
            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }

        #endregion

        #region Result

        /// <summary>
        /// 返回一个ResultSet  查询
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="sql"></param>
        /// <param name="pl"></param>
        /// <param name="tran"></param>
        /// <returns></returns>
        public ResultSet<T> GetResultSet<T>(string sql, string OrderBy, ParamList pl, IDbTransaction tran = null)
        {
            DBAdapter adapter = GetDBAdapter();

            try
            {
                var conn = adapter.OpenDatabase();
                if (pl.ispage)
                {
                    string pagesql = adapter.GetPageSql(sql, OrderBy);
                    string countsql = adapter.GetCountSql(sql);

                    var m = conn.Query<T>(pagesql, pl.GetParameters(), tran).ToList<T>();
                    var c = conn.ExecuteScalar<int>(countsql, pl.GetParameters(), tran);
                    return new ResultSet<T>() { Value = m, Total = c };
                }
                else
                {
                    var m = conn.Query<T>(sql + " order by " + OrderBy, pl.GetParameters(), tran).ToList<T>();
                    return new ResultSet<T>() { Value = m, Total = m.Count };
                }
            }
            catch
            {
                throw;
            }
            finally
            {
                adapter.CloseDatabase();
            }
        }

        /// <summary>
        /// 返回一个ResultSet  查询
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="OrderBy"></param>
        /// <param name="pl"></param>
        /// <param name="tran"></param>
        /// <returns></returns>
        public ResultSet GetResultSet(string sql, string OrderBy, ParamList pl, IDbTransaction tran = null)
        {
            DBAdapter adapter = GetDBAdapter();

            try
            {
                var conn = adapter.OpenDatabase();
                if (pl.ispage)
                {
                    string pagesql = adapter.GetPageSql(sql, OrderBy);
                    string countsql = adapter.GetCountSql(sql);

                    var m = conn.Query(pagesql, pl.GetParameters(), tran);
                    var c = conn.ExecuteScalar<int>(countsql, pl.GetParameters(), tran);
                    return ResultSet.GetResultSet(m, c);
                }
                else
                {
                    var m = conn.Query(sql + " order by " + OrderBy, pl.GetParameters(), tran);
                    return ResultSet.GetResultSet(m);
                }
            }
            catch
            {
                throw;
            }
            finally
            {
                adapter.CloseDatabase();
            }
        }
        #endregion

        #region 执行sql
        /// <summary>
        /// 执行sql，返回受影响记录数
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="model"></param>
        /// <param name="tran"></param>
        public int Execute(string sql, object model = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                return conn.Execute(sql, model, tran);

            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }
        /// <summary>
        /// 执行sql，返回受影响条记录数
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="pl"></param>
        /// <param name="tran"></param>
        /// <returns></returns>
        public int Execute(string sql, ParamList pl, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                return conn.Execute(sql, pl.GetParameters(), tran);

            }
            catch { throw; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }




        /// <summary>
        /// 同一个sql语句，批量操作多个对象
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="models"></param>
        /// <param name="tran"></param>
        public int Execute(string sql, IEnumerable<object> models, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                return conn.Execute(sql, models, tran);
            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }

        /// <summary>
        /// 使用事务批量执行多个语句
        /// </summary>
        /// <param name="sqllist"></param>
        /// <param name="pl"></param>
        /// <returns></returns>
        public void Execute(List<string> sqllist, object model = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                    tran = adapter.BeginTransaction();
                }
                var conn = tran.Connection;

                foreach (var sql in sqllist)
                {
                    conn.Execute(sql, model, tran);
                }
                if (adapter != null)
                {
                    adapter.Commit();
                }
            }
            catch
            {
                if (adapter != null)
                {
                    adapter.Rollback();
                }
                throw;
            }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }

        }
        /// <summary>
        /// 使用事务批量执行sql语句
        /// </summary>
        /// <param name="sqllist"></param>
        /// <param name="pl"></param>
        /// <param name="tran"></param>
        public void Execute(List<string> sqllist, ParamList pl, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                    tran = adapter.BeginTransaction();
                }
                var conn = tran.Connection;

                foreach (var sql in sqllist)
                {
                    conn.Execute(sql, pl.GetParameters(), tran);
                }
                if (adapter != null)
                {
                    adapter.Commit();
                }
            }
            catch
            {
                if (adapter != null)
                {
                    adapter.Rollback();
                }
                throw;
            }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }

        }
        #endregion

    }
}

     3.说明：

　　　　Dapper 相关目录结构如下：

　　　　

　　　　a.分成两个项目是为了避免数据库访问DBTools 被每层引用。除DAL层外，各层可以只引用CommonModel 就可以了.

　　　　b.使用DBAdapter 和DBFactory 对相关操作进行了封装，用于支持多数据库，目前我已经实现了MySqlDBAdapter,其他的数据库可以自行实现。

　　　　c. 使用时可以使用一个新的DB 类 对DBHelper 进行封装，达到方便调用，及同一个项目中使用多个数据库的目的，如在DAL 层中定义一个DB 类，类中包含一个静态DBHelper 对象，这样就可以向文中开始的那样调用DBHelper 了。

　　　　如下：

　　　　　　

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Configuration;

namespace MVC.DAL
{
    public class DB 
    {
        private static DBTools.DBHelper _instance;
        private static object lockhelper = new object();
        public static DBTools.DBHelper DBHelper
        {
            get
            {
                if (_instance == null)
                {
                    lock (lockhelper)
                    {
                        if (_instance == null)
                        {
                            _instance = new DBTools.DBHelper();
                            _instance.DBType = DBTools.DataBaseType.MySql;
                            _instance.ConnectionString = ConfigurationManager.ConnectionStrings["mysql"].ConnectionString;
                        }
                    }
                }
                return _instance;
            }
        }
    }
}