Dapper进行增删改查 z

http://www.cnblogs.com/huangkaiyan10/p/4640548.html

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 = 0;
            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 = 0;
            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 = 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;
        }
 
        public int UpdateUserRoleByUserId(UserRoleDbEntity model)
        {
            int affecgtRow = 0;
            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 = 0;
            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 = 0;
            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 = 1, 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。