Dapper.NET——轻量ORM

Dapper.NET使用

Dapper是一款轻量级ORM工具（Github）。如果你在小的项目中，使用Entity Framework、NHibernate 来处理大数据访问及关系映射，未免有点杀鸡用牛刀。你又觉得ORM省时省力，这时Dapper 将是你不二的选择。

1、为什么选择Dapper

1. 轻量。只有一个文件（SqlMapper.cs），编译完成之后只有120k(好象是变胖了)
2. 速度快。Dapper的速度接近与IDataReader，取列表的数据超过了DataTable。
3. 支持多种数据库。Dapper可以在所有Ado.net Providers下工作，包括sqlite, sqlce, firebird, oracle, MySQL, PostgreSQL and SQL Server
4. 可以映射一对一，一对多，多对多等多种关系。
5. 性能高。通过Emit反射IDataReader的序列队列，来快速的得到和产生对象，性能不错。
6. 支持FrameWork2.0，3.0，3.5，4.0，4.5

2、以Dapper（4.0）为例。

2.1 在数据库中建立几张表。

CREATE TABLE [dbo].[CICUser]
(
    [UserId]                [int] IDENTITY(1, 1) PRIMARY KEY NOT NULL,
    [Username]              [nvarchar](256) NOT NULL,
    [PasswordHash]          [nvarchar](500) NULL,
    [Email]                 [nvarchar](256) NULL,
    [PhoneNumber]           [nvarchar](30) NULL,
    [IsFirstTimeLogin]      [bit] DEFAULT(1) NOT NULL,
    [AccessFailedCount]     [int] DEFAULT(0) NOT NULL,
    [CreationDate]          [datetime] DEFAULT(GETDATE()) NOT NULL,
    [IsActive]              [bit] DEFAULT(1) NOT NULL
)

CREATE TABLE [dbo].[CICRole]
(
    [RoleId]       [int] IDENTITY(1, 1) PRIMARY KEY NOT NULL,
    [RoleName]     [nvarchar](256) NOT NULL,
)

CREATE TABLE [dbo].[CICUserRole]
(
     [Id]   [int] IDENTITY(1, 1) PRIMARY KEY NOT NULL,
     [UserId]  [int] FOREIGN KEY REFERENCES [dbo].[CICUser] ([UserId]) NOT NULL,
     [RoleId]  [int] FOREIGN KEY REFERENCES [dbo].[CICRole] ([RoleId]) NOT NULL
)

2.2实体类。

在创建实体类时，属性名称一定要与数据库字段一一对应。

public class User
    {
        public User()
        {
            Role = new List();
        }
        public int UserId { get; set; }
        public string UserName { get; set; }       
        public string Password { get; set; }
        public string Email { get; set; }
        public string PhoneNumber { get; set; }
        public bool IsFirstTimeLogin { get; set; }
        public int AccessFailedCount { get; set; }
        public DateTime CreationDate { get; set; }
        public bool IsActive { get; set; }
        public List Role { get; set; }
    }
 public class Role
    {
        public int RoleId { get; set; }
        public string RoleName { get; set; }
    }
 public class Customer
    {
        public int UserId { get; set; }
        public string UserName { get; set; }       
        public string Password { get; set; }
        public string Email { get; set; }
        public string PhoneNumber { get; set; }
        public bool IsFirstTimeLogin { get; set; }
        public int AccessFailedCount { get; set; }
        public DateTime CreationDate { get; set; }
        public bool IsActive { get; set; }
        public Role Role { get; set; }
    }    

实体类

3.使用方法

3.1  一对一映射

 private static void OneToOne(string sqlConnectionString)
        {
            List userList = new List();
            using (IDbConnection conn = GetSqlConnection(sqlConnectionString))
            {
                string sqlCommandText = @"SELECT c.UserId,c.Username AS UserName,
c.PasswordHash AS [Password],c.Email,c.PhoneNumber,c.IsFirstTimeLogin,c.AccessFailedCount,
c.CreationDate,c.IsActive,r.RoleId,r.RoleName 
    FROM dbo.CICUser c WITH(NOLOCK) 
INNER JOIN CICUserRole cr ON cr.UserId = c.UserId 
INNER JOIN CICRole r ON r.RoleId = cr.RoleId";
                userList = conn.Query(sqlCommandText, 
                                                                (user, role) => { user.Role = role; return user; },
                                                                null,
                                                                null,
                                                                true, 
                                                                "RoleId", 
                                                                null,
                                                                null).ToList();
            }

            if (userList.Count > 0)
            {
                userList.ForEach((item) => Console.WriteLine("UserName:" + item.UserName +
                                                             "----Password:" + item.Password + 
                                                             "-----Role:" + item.Role.RoleName +
                                                             "\n"));

                Console.ReadLine();
            }
        }

3.2 一对多映射

private static void OneToMany(string sqlConnectionString)
        {
            Console.WriteLine("One To Many");
            List userList = new List();

            using (IDbConnection connection = GetSqlConnection(sqlConnectionString))
            {

                string sqlCommandText3 = @"SELECT c.UserId,
       c.Username      AS UserName,
       c.PasswordHash  AS [Password],
       c.Email,
       c.PhoneNumber,
       c.IsFirstTimeLogin,
       c.AccessFailedCount,
       c.CreationDate,
       c.IsActive,
       r.RoleId,
       r.RoleName
FROM   dbo.CICUser c WITH(NOLOCK)
       LEFT JOIN CICUserRole cr
            ON  cr.UserId = c.UserId
       LEFT JOIN CICRole r
            ON  r.RoleId = cr.RoleId";

                var lookUp = new Dictionary<int, User>();
                userList = connection.Query(sqlCommandText3,
                    (user, role) =>
                    {
                        User u;
                        if (!lookUp.TryGetValue(user.UserId, out u))
                        {
                            lookUp.Add(user.UserId, u = user);
                        }
                        u.Role.Add(role);
                        return user;
                    }, null, null, true, "RoleId", null, null).ToList();
                var result = lookUp.Values;
            }

            if (userList.Count > 0)
            {
                userList.ForEach((item) => Console.WriteLine("UserName:" + item.UserName +
                                             "----Password:" + item.Password +
                                             "-----Role:" + item.Role.First().RoleName +
                                             "\n"));

                Console.ReadLine();
            }
            else
            {
                Console.WriteLine("No Data In UserList!");
            }
        }

3.3 插入实体

 public static void InsertObject(string sqlConnectionString)
        {
            string sqlCommandText = @"INSERT INTO CICUser(Username,PasswordHash,Email,PhoneNumber)VALUES(
    @UserName,
    @Password,
    @Email,
    @PhoneNumber
)";
            using (IDbConnection conn = GetSqlConnection(sqlConnectionString))
            {
                User user = new User();
                user.UserName = "Dapper";
                user.Password = "654321";
                user.Email = "[email protected]";
                user.PhoneNumber = "13795666243";
                int result = conn.Execute(sqlCommandText, user);
                if (result > 0)
                {
                    Console.WriteLine("Data have already inserted into DB!");
                }
                else
                {
                    Console.WriteLine("Insert Failed!");
                }

                Console.ReadLine();
            }
        }

3.4 执行存储过程

         /// 

        /// Execute StoredProcedure and map result to POCO
        /// 
        /// 
        public static void ExecuteStoredProcedure(string sqlConnnectionString)
        {
            List users = new List();
            using (IDbConnection cnn = GetSqlConnection(sqlConnnectionString))
            {
                users = cnn.Query("dbo.p_getUsers", 
                                        new { UserId = 2 },
                                        null, 
                                        true, 
                                        null, 
                                        CommandType.StoredProcedure).ToList();
            }
            if (users.Count > 0)
            {
                users.ForEach((user) => Console.WriteLine(user.UserName + "\n"));
            }
            Console.ReadLine();
        }

        /// 

        /// Execute StroedProcedure and get result from return value
        /// 
        /// 
        public static void ExecuteStoredProcedureWithParms(string sqlConnnectionString)
        {
            DynamicParameters p = new DynamicParameters();
            p.Add("@UserName", "cooper");
            p.Add("@Password", "123456");
            p.Add("@LoginActionType", null, DbType.Int32, ParameterDirection.ReturnValue);
            using (IDbConnection cnn = GetSqlConnection(sqlConnnectionString))
            {
                cnn.Execute("dbo.p_validateUser", p, null, null, CommandType.StoredProcedure);
                int result = p.Get<int>("@LoginActionType");
                Console.WriteLine(result);
            }

            Console.ReadLine();
        }

 

转载于:https://www.cnblogs.com/yankliu-vip/p/4182892.html