使用轻量级ORM Dapper进行增删改查

  项目背景

前一段时间，开始做一个项目，在考虑数据访问层是考虑技术选型，考虑过原始的ADO.NET、微软的EF、NH等。再跟经理讨论后，经理强调不要用Ef，NH做ORM，后期的sql优化不好做，公司也没有人对EF，Nh 等orm优化比较熟悉的。强调说的，我们的项目要做的得简单，可以使用ADO.NET 写原始的sql。但我自己还是喜欢ORM的，它可以提高数据访问层的开发。有一天，在订阅张善友 doNet跨平台微信公众号里，看到Dapper的推荐。了解之后，我自己喜欢喜欢Dapper，可以满足我这个项目的经理的要求，同时Dapper 对数据库的访问能做到Ado.net一样快。

下面的链接是Dapper 在github的地址  https://github.com/StackExchange/dapper-dot-net。

使用 Dapper 进行简单增删改查示例

   1、首先根据数据库表定义实体对象， 这个工作完全可以使用T4、Nvelocity或者RazorEngine 写一个代码生成器根据数据库表对象自动生成数据库表实体对象。这里我自己根据表写了一个对象

    [Table("UserRole")]
    public class UserRoleDbEntity:DbEntityModelBase
     {
         [Description("用户编号，来自用户表")]
         public int UserId
         {
             get;
             set;
         }

        [Description("角色编号，来自于角色表")]
         public int RoleId
         {
             get;
             set;
         }
         /// <summary>
         /// 备注：AuthorityEnum.AuthorityValue 的取值范围是根据 AuthorityEnum位运算 或 与 的结果集；不可随意赋值
         /// </summary>
         [Description("权限值")]
         public int AuthorityValue { get; set; }

         /// <summary>
         /// 根据 AuthorityEnum 枚举值生成的描述
         /// </summary>
         [Description("权限描述")]
         public string AuthorityDescription { get; set; }
     }

     /// <summary>
     /// 所有DbEntityModel项目中的实体必须继承DbEntityModelBase或其子类，使用supperType模式控制共有子类的行为或者状态，此项目中的类根据数据库基本表或者视图保持基本一致
     /// </summary>
    public abstract class DbEntityModelBase
     {
         [Description("Guid标识")]
         public string GuidMark
         {
             get;
             set;
         }
         [Description("自增Id列")]
         public int Id
         {
             get;
             set;
         }
        [Description("排序，倒序")]
         public int Sort
         {
             get;
             set;
         }
     }

2. 在DAL层就可以使用实体对象传参 或者作为返回值

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using OnlineExercise.DbAccess;
 using Dapper;
 using System.Configuration;
 using System.Data;
 using MySql.Data;
 using MySql.Data.MySqlClient;
 using OnlineExercise.DbEntityModel;
 using OnlineExercise.Log;
 using OnlineExercise.Infrastructrue;

 namespace OnlineExercise.DbAccess.SysAdminModule
 {
     public class UserRoleDB:DalBase<UserRoleDB>
     {
         public int AddUserRole(UserRoleDbEntity model)
         {
             int affecgtRow = ;
             string sql = @"INSERT INTO  `userrole`
                                     (`GuidMark`,
                                      `UserId`,
                                      `RoleId`,
                                      `AuthorityValue`,
                                      `AuthorityDescription`)
                         VALUES (@GuidMark,
                                 @UserId,
                                 @RoleId,
                                 @AuthorityValue,
                                 @AuthorityDescription);";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 affecgtRow = conn.Execute(sql, model);
             }
             return affecgtRow;
         }

         public int UpdateUserRoleByRoleIdAndUserId(UserRoleDbEntity model)
         {
             int affecgtRow = ;
             string sql = @"UPDATE  `userrole`
                             SET  `AuthorityValue` = @AuthorityValue,
                                 `AuthorityDescription` = @AuthorityDescription
                             WHERE `UserId` = @UserId
                                 AND `RoleId` = @RoleId;";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 affecgtRow = conn.Execute(sql, model);
             }
             return affecgtRow;
         }

         public int UpdateUserRoleByRoleId(UserRoleDbEntity model)
         {
             int affecgtRow = ;
             string sql = @"UPDATE  `userrole`
                             SET  `AuthorityValue` = @AuthorityValue,
                                 `AuthorityDescription` = @AuthorityDescription
                             WHERE `RoleId` = @RoleId;";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 affecgtRow = conn.Execute(sql, model);
             }
             return affecgtRow;
         }

         public int UpdateUserRoleByUserId(UserRoleDbEntity model)
         {
             int affecgtRow = ;
             string sql = @"UPDATE  `userrole`
                             SET  `AuthorityValue` = @AuthorityValue,
                                 `AuthorityDescription` = @AuthorityDescription
                             WHERE `UserId` = @UserId;";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 affecgtRow = conn.Execute(sql, model);
             }
             return affecgtRow;
         }

         public List<UserRoleDbEntity> GetUserRoleListByRoleId(UserRoleDbEntity model)
         {
             List<UserRoleDbEntity> modelList = null;
             string sql = @"SELECT
                               `Id`,
                               `GuidMark`,
                               `sort`,
                               `UserId`,
                               `RoleId`,
                               `AuthorityValue`,
                               `AuthorityDescription`
                             FROM `userrole`
                             WHERE RoleId=@RoleId;";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 modelList = conn.Query<UserRoleDbEntity>(sql, model).ToList<UserRoleDbEntity>();
             }
             return modelList;
         }

         public List<UserRoleDbEntity> GetUserRoleListByUserId(string userId)
         {
             List<UserRoleDbEntity> modelList = null;
             string sql = @"SELECT
                               `Id`,
                               `GuidMark`,
                               `sort`,
                               `UserId`,
                               `RoleId`,
                               `AuthorityValue`,
                               `AuthorityDescription`
                             FROM `userrole`
                             WHERE UserId=@UserId;";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 modelList = conn.Query<UserRoleDbEntity>(sql, new { UserId =userId}).ToList<UserRoleDbEntity>();
             }
             return modelList;
         }

         public List<UserRoleDbEntity> GetUserRoleListByRoleIdAndUserId(UserRoleDbEntity model)
         {
             List<UserRoleDbEntity> modelList = null;
             string sql = @"SELECT
                               `Id`,
                               `GuidMark`,
                               `sort`,
                               `UserId`,
                               `RoleId`,
                               `AuthorityValue`,
                               `AuthorityDescription`
                             FROM `userrole`
                             WHERE RoleId=@RoleId and UserId=@UserId;";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 modelList = conn.Query<UserRoleDbEntity>(sql, model).ToList<UserRoleDbEntity>();
             }
             return modelList;
         }

         public int DeleteUserRoleByUserId(string userId)
         {
             int affecgtRow = ;
             string sql = @"DELETE
                             FROM  `userrole`
                             WHERE `UserId` = @UserId";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 affecgtRow = conn.Execute(sql, new { UserId = userId });
             }
             return affecgtRow;
         }

         public int DeleteUserRoleByRoleId(string roleId)
         {
             int affecgtRow = ;
             string sql = @"DELETE
                             FROM  `userrole`
                             WHERE `RoleId` = @RoleId;";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 affecgtRow = conn.Execute(sql, new { RoleId = roleId });

             }
             return affecgtRow;
         }

         public DataTable GetRoleInfoByUserId(string userId)
         {
             DataTable dt = null;

             string sql = @"SELECT b.*,a.userid,c.name as userName  FROM userrole AS a
                                 INNER JOIN role AS b ON a.roleid=b.id
                                 INNER JOIN USER AS c ON c.id=a.userid
                                 WHERE a.userid=@userid;";
             using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
             {
                 IDataReader reader = conn.ExecuteReader(sql, new { userid=userId });
                 dt = CoreUtil.DataReader2Table(reader);
                 reader.Dispose();
             }

             return dt;
         }

     }
 }

  Dapper的优势

1、Dapper是一个轻型的ORM类

2、 Dapper语法简单，如果你喜欢写原始的sql，你一定喜欢Dapper。同时团队人员也很容易上手

3、Dapper 速度快，速度接近ADO.NET访问数据库的效率。

4、多数据库切换方便

public int UpdateUserRoleByRoleId(UserRoleDbEntity model)
        {
            int affecgtRow = 0;
            string sql = @"UPDATE  `userrole`
                            SET  `AuthorityValue` = @AuthorityValue,
                                `AuthorityDescription` = @AuthorityDescription
                            WHERE `RoleId` = @RoleId;";
            using (IDbConnection conn = new MySqlConnection(GlobalVariablesManager.G_Strconn))
            {
                affecgtRow = conn.Execute(sql, model);
            }
            return affecgtRow;
        }

这里mysql如果要切换为Sql Server ，只要修改链接  MySqlConnection---》SqlConnection。

Dapper更多特性

1、支持动态dynamic绑定

 var rows = connection.Query("select 1 A, 2 B union all select 3, 4");

 ((int)rows[].A)
    .IsEqualTo();

 ((int)rows[].B)
    .IsEqualTo();

 ((int)rows[].A)
    .IsEqualTo();

 ((int)rows[].B)
     .IsEqualTo();

2、支持批量插入

 connection.Execute(@"insert MyTable(colA, colB) values (@a, @b)",
     new[] { new { a=, b= }, new { a=, b= }, new { a=, b= } }
   ).IsEqualTo(); // 3 rows inserted: "1,1", "2,2" and "3,3"

3、支持多表关联

 var sql =
 @"select * from #Posts p
 left join #Users u on u.Id = p.OwnerId
 Order by p.Id";

 var data = connection.Query<Post, User, Post>(sql, (post, user) => { post.Owner = user; return post;});
 var post = data.First();

 post.Content.IsEqualTo("Sams Post1");
 post.Id.IsEqualTo();
 post.Owner.Name.IsEqualTo("Sam");
 post.Owner.Id.IsEqualTo();

4、支持多结果查询

 var sql =
 @"
 select * from Customers where CustomerId = @id
 select * from Orders where CustomerId = @id
 select * from Returns where CustomerId = @id";

 using (var multi = connection.QueryMultiple(sql, new {id=selectedId}))
 {
    var customer = multi.Read<Customer>().Single();
    var orders = multi.Read<Order>().ToList();
    var returns = multi.Read<Return>().ToList();
    ...
 } 

5 支持存储过程

 var user = cnn.Query<User>("spGetUser", new {Id = },
         commandType: CommandType.StoredProcedure).SingleOrDefault();
 // 你还可以获取存储过程out参数的输出值或者返回值
 var p = new DynamicParameters();
 p.Add("@a", );
 p.Add("@b", dbType: DbType.Int32, direction: ParameterDirection.Output);
 p.Add("@c", dbType: DbType.Int32, direction: ParameterDirection.ReturnValue);

 cnn.Execute("spMagicProc", p, commandType: CommandType.StoredProcedure); 

 int b = p.Get<int>("@b");
 int c = p.Get<int>("@c"); 

6、参数自动绑定

 new {A = , B = "b"} // A will be mapped to the param @A, B to the param @B 

 看到Dapper那么特性，觉得使用Dapper非常方便，使用也非常方便，扩展性也非常高。 当我用Dapper写一个demo给项目经理看的时候，项目经理就同意使用
Dapper 作为ORM 进行数据访问层的开发。从此就爱上了Dapper。
   希望这篇文章给你带来对Dapper清晰的了解。同时如果这文章给你到来了帮助，也别忘了帮忙推荐。