一、Dapper基本操作

 參考資料：Cooper Liu 毒逆天

 

 一、Dapper安裝

　　添加引用-->NuGet管理-->搜索Dapper-->安裝

 

二、新建表　

--創建一個員工表
create table Employee
(
    Em_Id int identity(1,1) primary key,
    Em_Name varchar(50) not null,
    Em_Age int default(18) not null
)

--部門表
Create Table Department
(
    Depart_Id int identity(1,1) primary key,
    Depart_Name varchar(20) not null,    
)

--員工所屬部門關系表
Create table EmployeePartment
(
    EP_Id int identity(1,1) primary key,
    Em_Id int not null,
    Depart_Id int not null
)

 

三、新建實體類

　　實體類屬性要與數據庫中的字段名稱對應

/// <summary>
    /// 生成Employee實體，注意類屬性與表字段要一一對應
    /// </summary>
    public class Employee
    {
        public int Em_Id { get; set; }
        public string Em_Name { get; set; }

        public int Em_Age { get; set; }
    }
    /// <summary>
    /// 生成部門Department實體
    /// </summary>
    public class Department
    {
        public int Depart_Id { get; set; }
        public string Depart_Name { get; set; }
    }

    /// <summary>
    /// 生成部門員工所屬部門對應關系
    /// </summary>
    public class EmployeePartment
    {
        public int EP_Id { get; set; }
        public int Em_Id { get; set; }
        public int Depart_Id { get; set; }
    }

四、插入操作

　　Dapper支持單個插入，也支持批量插入(Bulk)，支持存儲過程進行插入操作。

/// <summary>
        /// 聲明object類型可用單個對象時插入單對象，也可批量BulkInsert插入(只要實現IEnumable接口)
        /// </summary>
        /// <param name="obj"></param>
        private static void InsertEmployee(Object obj)
        {
            using (var conn = GetConnection())
            {
                string sql = "insert into employee values (@Em_Name,@Em_Age)";
                int result = conn.Execute(sql, obj);
            }
        }

        /// <summary>
        /// 插入部門操作
        /// </summary>
        /// <param name="depart"></param>
        private static void InsertDepartment(object depart)
        {
            CommandDefinition command = new CommandDefinition("insert into department values (@Depart_Name)", depart);
            using (var conn=GetConnection())
            {
                conn.Execute(command);
            }

        }

        /// <summary>
        /// 生成sqlConnection對象。返回IDbConnection.
        /// </summary>
        /// <returns></returns>
        private static IDbConnection GetConnection()
        {
            var conn = new SqlConnection(connstr);
            return conn;
        }

　　示例中使用了conn.Execute()方法，該方法兩個種形式的重載。

 

　　　　1、public static int Execute(this IDbConnection cnn, CommandDefinition command);

　　　　2、public static int Execute(this IDbConnection cnn, string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null);

　　　　雖說是兩種形式，其實質是CommandDefinition對重載的第二個方法條件進行了封閉。由CommandDefinition構造函數定義可以看到對應關系。

　　　　 public CommandDefinition(string commandText, object parameters = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null, CommandFlags flags = CommandFlags.Buffered);

　　 Execute是IDbConnection的擴展方法，所以conn可以直接調用。

五、刪除操作

　　Dapper支持sql語句刪除操作，也支持存儲過程刪除操作

//此處為方法調用
 //Ado.net方法刪除
 DeleteEmployeeById(1);

UseCommandDeleteEmployeeUseById(2);

//存儲過程刪除
ProcDeleteEmployeeById(3);

//此處為方法實現
 /// <summary>
        /// 根據ID刪除對應Employee
        /// </summary>
        /// <param name="id">待刪除的EmployeeId</param>
        private static void DeleteEmployeeById(int id)
        {
            using (var conn=GetConnection())
            {
               int result= conn.Execute("delete from Employee where EM_Id=@id", new { @id = id });
            }
        }

        /// <summary>
        /// 使用Command形式刪除操作
        /// </summary>
        /// <param name="id">待刪除的Employee的ID</param>
        private static void UseCommandDeleteEmployeeUseById(int id)
        {
            var command = new CommandDefinition("delete from Employee where Em_Id=@Eid", new { @Eid = id }, null, null, CommandType.Text,CommandFlags.None);

            using (var conn=GetConnection())
            {
                int result = conn.Execute(command);
            }
        }
        /// <summary>
        /// 使用存儲過程形式刪除Employee
        /// </summary>
        /// <param name="id">待刪除的Employee</param>
        private static void ProcDeleteEmployeeById(int id)
        {
            using (var conn = GetConnection())
            {
               int result= conn.Execute("pr_delete_employee", new { @id = id },null,null,CommandType.StoredProcedure);
            }
        }

　　刪除示例中也是使用conn.Execute()方法進行操作。

六、更新操作

　　操作同新增、刪除同樣使用conn.Execute()方法進行。

//方法調用
  UpdateEmployeeName(4, "新名稱");

  UseCommandUpdateEmployee(4, 18);

  ProcUpdateEmployeeName(5, "舊名稱");
//方法實現
    

        /// <summary>
        /// 更新指定ID名稱為新值
        /// </summary>
        /// <param name="eid">Employee的Id</param>
        /// <param name="name">新的employee名稱</param>
        private static void UpdateEmployeeName(int eid, string name)
        {
            using (var conn=GetConnection())
            {
               int result= conn.Execute("update Employee set Em_Name=@name where Em_Id=@id", new { @name = name, @id = eid });
            }
        }

        /// <summary>
        /// 使用Command形式更新Employee信息
        /// </summary>
        /// <param name="eid">待更新的EmployeeId</param>
        /// <param name="Age">Age新值</param>
        private static void UseCommandUpdateEmployee(int eid, int Age)
        {
            var command=new CommandDefinition("update Employee set Em_Age=@age where em_Id=@eid",new{@age=Age,@eid=eid},null,null,CommandType.Text,CommandFlags.None);
            using (var conn=GetConnection())
            {
                int result = conn.Execute(command);
            }
        }

        /// <summary>
        /// 更新指定ID名稱為新值
        /// </summary>
        /// <param name="eid">Employee的Id</param>
        /// <param name="name">新的employee名稱</param>
        private static void ProcUpdateEmployeeName(int eid, string name)
        {
            using (var conn = GetConnection())
            {
                var p = new DynamicParameters();
                p.Add("@id", eid);
                p.Add("@name", name);
                int result = conn.Execute("pr_update_employee", new {  id = eid,name = name },null,null,CommandType.StoredProcedure));
            }
        }

七、查找操作　　　

//簡單查詢
            Employee employee = GetEmployeeById(5);
            if (employee != null)
            {
                Console.WriteLine("ID為5的員工已找到名稱:" + employee.Em_Name);
            }

            //子查詢
            List<Employee> list_employees = GetEmployeesByPartId(1);
            Console.WriteLine("共找到{0}記錄:", list_employees.Count);
            for (int i = 0; i < list_employees.Count; i++)
            {
                Console.Write(list_employees[i].Em_Name + ",");
            }

            //多返回值
            GetMutile();
/// <summary>
        /// 根據ID查找EmpolyeeID 支持ADO語句和存儲過程
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        private static Employee GetEmployeeById(int id)
        {
            Employee employee = new Employee();
            using (var conn = GetConnection())
            {
                employee = conn.Query<Employee>("select * from employee where Em_Id=@id", new { id = id }).FirstOrDefault();

            }

            //CommandDefinition command = new CommandDefinition("select * from employee wehre em_id=@id");

            //using (var conn = GetConnection())
            //{
            //    employee = conn.Query<Employee>(command).FirstOrDefault();

            //}

            return employee;
        }

        /// <summary>
        /// 子查詢
        /// </summary>
        /// <param name="partid"></param>
        /// <returns></returns>
        private static List<Employee> GetEmployeesByPartId(int partid)
        {
            List<Employee> employees = new List<Employee>();

            CommandDefinition command = new CommandDefinition("select * from employee where em_id in (select em_id from  EmployeePARTMENT where Depart_Id=@id) ", new { id = partid });

            using (var conn = GetConnection())
            {
                employees = conn.Query<Employee>(command).ToList();
            }
            return employees;
        }

        /// <summary>
        /// 多返回值查詢
        /// </summary>
        private static void GetMutile()
        {
            string sql = @"select * from [Employee];
                     select  *  from [Department]";
            CommandDefinition command = new CommandDefinition(sql);

            using (var conn = GetConnection())
            {
                var muitle = conn.QueryMultiple(sql);
                //var muitle=conn.QueryMultiple(command);
                if (!muitle.IsConsumed)
                {
                    //強類型讀取
                    //var employees = muitle.Read<Employee>();
                    //var deparements = muitle.Read<Department>();

                    //動態類型讀取
                    var employees = muitle.Read();
                    var deparements = muitle.Read();

                    foreach (var item in employees)
                    {
                        Console.WriteLine(item.Em_Name + ":" + item.Em_Age.ToString());
                    }

                    Console.WriteLine();

                    foreach (var item in deparements)
                    {
                        Console.WriteLine(item.Depart_Name + ":" + item.Depart_Id);
                    }

                }
            }
        }

八、總結

　　使用Dapper進行增刪改查、存儲過程調用、多表值返回操作。