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 > )
             {
                 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;
             }
         }
     }
 }