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

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)
速度快。Dapper的速度接近与IDataReader，取列表的数据超过了DataTable。
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
可以映射一对一，一对多，多对多等多种关系。
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。
支持FrameWork2.0，3.0，3.5，4.0，4.5

2、以Dapper（4.0）为例。

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.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<Role>();        }        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> 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<Customer> userList = new List<Customer>();            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<Customer, Role, Customer>(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<User> userList = new List<User>();            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.RoleNameFROM   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<User, Role, User>(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 = "Dapper@infosys.com";                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

         /// <summary>        /// Execute StoredProcedure and map result to POCO        /// </summary>        /// <param name="sqlConnnectionString"></param>        public static void ExecuteStoredProcedure(string sqlConnnectionString)        {            List<User> users = new List<User>();            using (IDbConnection cnn = GetSqlConnection(sqlConnnectionString))            {                users = cnn.Query<User>("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();        }

        /// <summary>        /// Execute StroedProcedure and get result from return value        /// </summary>        /// <param name="sqlConnnectionString"></param>        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();        }

Dapper.NET——轻量ORM

声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉：投诉/举报工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。

联系
我们

首页 > 代码库 > Dapper.NET——轻量ORM