Dapper简单介绍：

Dapper is a single file you can drop in to your project that will extend your IDbConnection interface.

Dapper是一个轻型的开源ORM类，代码就一个SqlMapper.cs文件，编译后就40多K的一个很小的Dll. 官方资料：点击这里

Dapper支持Mysql,SqlLite,Mssql2000,Mssql2005,Oracle等一系列的数据库，当然如果你知道原理也可以让它支持Mongo db

Dapper的r支持多表并联的对象。支持一对多 多对多的关系。并且没侵入性，想用就用，不想用就不用。无XML无属性。代码以前怎么写现在还怎么写。

Dapper原理通过Emit反射IDataReader的序列队列，来快速的得到和产生对象。性能提升了很多；（比采用常规的反射）

Dapper支持net2.0,3.0,3.5,4.0。不过就是要配置下。如果不知道如何配置查看我博客里的在2.0下使用3.5就可以了。

语法十分简单。并且无须迁就数据库的设计。

Dapper的使用：

使用Nuget安装：

在解决方案管理器中点击项目，查看引用，如果有Dapper，说明安装成功。

Dapper的基本用法

首先配置连接字符串，这里以Sql Server为例：

配置数据库连接字符串如下

<connectionStrings>

<add name="connectionString" connectionString="server=.;user id=sa;password=123456;database=Dapper"/>

</connectionStrings>

使用dapper进行插入操作

private static readonly string connectionString = ConfigurationManager.ConnectionStrings["connectionString"].ToString();
/// <summary>
/// 使用Dapper添加单条数据操作
/// </summary>
/// <param name="student"></param>
/// <returns></returns>
public static int Insert(Student student)
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        return connection.Execute("insert into Student(UserName,Name) values(@UserName,@Name)", student);
    }
}
/// <summary>
/// 批量插入Student数据，返回影响行数
/// </summary>
/// <param name="student"></param>
/// <returns>影响行数</returns>
public static int Insert(List<Student> student)
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        return connection.Execute("insert into Student(UserName,Name) values(@UserName,@Name)", student);
    }
}

使用dapper进行删除操作

/// <summary>
/// 使用Dapper删除单条学生记录
/// </summary>
/// <param name="student"></param>
/// <returns></returns>
public static int Delete(Student student)
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
         return connection.Execute("DELETE FROM Student WHERE Id=@Id", student);
    }
}
/// <summary>
/// 使用Dapper批量删除学生记录
/// </summary>
/// <param name="Students"></param>
/// <returns></returns>
public static int Delete(List<Student> student)
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        return connection.Execute("DELETE FROM Student WHERE Id=@Id", student);
    }
}

使用dapper进行修改操作

/// <summary>
/// 单条记录修改
/// </summary>
/// <param name="student"></param>
/// <returns></returns>
public static int Update(Student student)
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        return connection.Execute("update Student set name=@name where Id=@Id", student);
    }
}
/// <summary>
/// 批量修改
/// </summary>
/// <param name="student"></param>
/// <returns></returns>
public static int Update(List<Student> student)
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        return connection.Execute("update Student set name=@name where Id=@Id", student);
    }
}

使用dApper进行查询操作

/// <summary>
/// 无参查询所有数据
/// </summary>
/// <returns></returns>
public static List<Student> Query()
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        return connection.Query<Student>("select * from Student").ToList();
    }
}
/// <summary>
/// 查询指定数据
/// </summary>
/// <param name="Student"></param>
/// <returns></returns>
public static Student Query(Student Student)
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        return connection.Query<Student>("select * from Student where Id=@Id", Student).SingleOrDefault();
    }
}

Dapper下In查询

/// <summary>
/// In查询
/// </summary>
public static List<Student> QueryIn()
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        var sql = "select * from Student where Id in @Ids";
        //参数类型是Array的时候，dappper会自动将其转化 
        return connection.Query<Student>(sql, new { ids = new int[2] { 1, 2 }, }).ToList();
    }
}
/// <summary>
/// In查询
/// </summary>
/// <param name="ids"></param>
/// <returns></returns>
public static List<Student> QueryIn(int[] ids)
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        var sql = "select * from Student where id in @ids";
        //参数类型是Array的时候，dappper会自动将其转化 
        return connection.Query<Student>(sql, new { ids }).ToList();
    }
}

dapper 下多语句查询

/// <summary>
/// 多语句操作
/// </summary>
public static void QueryMultiple()
{
    using (IDbConnection connection = new SqlConnection(connectionString))
    {
        var sql = "select * from Student; select * from Socre";
        var multiReader = connection.QueryMultiple(sql);
        var StudentList = multiReader.Read<Student>();
        var bookList = multiReader.Read<Socre>();
        multiReader.Dispose();
    }
}

总结

dapper使用起来，轻便快捷，灵活。运行速度快。