Dapper.NET使用
本文目录
- Dapper.NET使用
- 1、为什么选择Dapper
- 2、以Dapper（4.0）为例。
- 2.1 在数据库中建立几张表。
- 2.2实体类。
- 3.使用方法
- 3.1 一对一映射
- 3.2 一对多映射
- 3.3 插入实体
- 3.4 执行存储过程
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。
访问量不大的项目可以考虑用EF写数据库操作，因为EF除了速度上慢以外，但开发效率极快，省略了很多sql写法，并能很方便的调用外键、集合等信息，用EF写项目最爽的事。
不过有些项目网站要考虑运行速度，这时不得不用其它的ORM框架，比如用Dapper，因为它速度快，而且写sql非常灵活。
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
- Dapper语法十分简单。并且无须迁就数据库的设计
2、以Dapper（4.0）为例
先通过NuGet进行安装Dapper
PM> Install-Package Dapper -Version 1.40.
2.1 在数据库中建立几张表
CREATE TABLE [dbo].[CICUser]
(
[UserId] [int] IDENTITY(, ) PRIMARY KEY NOT NULL,
[Username] [nvarchar]() NOT NULL,
[PasswordHash] [nvarchar]() NULL,
[Email] [nvarchar]() NULL,
[PhoneNumber] [nvarchar]() NULL,
[IsFirstTimeLogin] [bit] DEFAULT() NOT NULL,
[AccessFailedCount] [int] DEFAULT() NOT NULL,
[CreationDate] [datetime] DEFAULT(GETDATE()) NOT NULL,
[IsActive] [bit] DEFAULT() NOT NULL
) CREATE TABLE [dbo].[CICRole]
(
[RoleId] [int] IDENTITY(, ) PRIMARY KEY NOT NULL,
[RoleName] [nvarchar]() NOT NULL,
) CREATE TABLE [dbo].[CICUserRole]
(
[Id] [int] IDENTITY(, ) 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<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; }
}
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 > )
{
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.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<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 > )
{
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 = "";
user.Email = "Dapper@infosys.com";
user.PhoneNumber = "";
int result = conn.Execute(sqlCommandText, user);
if (result > )
{
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 = },
null,
true,
null,
CommandType.StoredProcedure).ToList();
}
if (users.Count > )
{
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", "");
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();
}