参考资料：Cooper Liu 毒逆天
一、Dapper安装
添加引用-->NuGet管理-->搜索Dapper-->安装
二、新建表
--创建一个员工表
create table Employee
(
Em_Id int identity(1,1) primary key,
Em_Name varchar(50) not null,
Em_Age int default(18) not null
)
--部门表
Create Table Department
(
Depart_Id int identity(1,1) primary key,
Depart_Name varchar(20) not null,
)
--员工所属部门关系表
Create table EmployeePartment
(
EP_Id int identity(1,1) primary key,
Em_Id int not null,
Depart_Id int not null
)
三、新建实体类
实体类属性要与数据库中的字段名称对应
/// <summary>
/// 生成Employee实体，注意类属性与表字段要一一对应
/// </summary>
public class Employee
{
public int Em_Id { get; set; }
public string Em_Name { get; set; }
public int Em_Age { get; set; }
}
/// <summary>
/// 生成部门Department实体
/// </summary>
public class Department
{
public int Depart_Id { get; set; }
public string Depart_Name { get; set; }
}
/// <summary>
/// 生成部门员工所属部门对应关系
/// </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支持单个插入，也支持批量插入(Bulk)，支持存储过程进行插入操作。
/// <summary>
/// 声明object类型可用单个对象时插入单对象，也可批量BulkInsert插入(只要实现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>
/// 插入部门操作
/// </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对象。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，该方法两个种形式的重载。
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);
虽说是两种形式，其实质是CommandDefinition对重载的第二个方法条件进行了封闭。由CommandDefinition构造函数定义可以看到对应关系。
public CommandDefinition(string commandText, object parameters = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null, CommandFlags flags = CommandFlags.Buffered);
Execute是IDbConnection的扩展方法，所以conn可以直接调用。
五、删除操作
Dapper支持sql语句删除操作，也支持存储过程删除操作
//此处为方法调用
//Ado.net方法删除
DeleteEmployeeById(1);
UseCommandDeleteEmployeeUseById(2);
//存储过程删除
ProcDeleteEmployeeById(3);
//此处为方法实现
/// <summary>
/// 根据ID删除对应Employee
/// </summary>
/// <param name="id">待删除的EmployeeId</param>
private static void DeleteEmployeeById(int id)
{
using (var conn=GetConnection())
{
int result= conn.Execute("delete from Employee where [email protected]", new { @id = id });
}
}
/// <summary>
/// 使用Command形式删除操作
/// </summary>
/// <param name="id">待删除的Employee的ID</param>
private static void UseCommandDeleteEmployeeUseById(int id)
{
var command = new CommandDefinition("delete from Employee where [email protected]", new { @Eid = id }, null, null, CommandType.Text,CommandFlags.None);
using (var conn=GetConnection())
{
int result = conn.Execute(command);
}
}
/// <summary>
/// 使用存储过程形式删除Employee
/// </summary>
/// <param name="id">待删除的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);
}
}
删除示例中也是使用conn.Execute()方法进行操作。
六、更新操作
操作同新增、删除同样使用conn.Execute()方法进行。
//方法调用
UpdateEmployeeName(4, "新名称");
UseCommandUpdateEmployee(4, 18);
ProcUpdateEmployeeName(5, "旧名称");
//方法实现
/// <summary>
/// 更新指定ID名称为新值
/// </summary>
/// <param name="eid">Employee的Id</param>
/// <param name="name">新的employee名称</param>
private static void UpdateEmployeeName(int eid, string name)
{
using (var conn=GetConnection())
{
int result= conn.Execute("update Employee set [email protected] where [email protected]", 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 [email protected] where [email protected]",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名称为新值
/// </summary>
/// <param name="eid">Employee的Id</param>
/// <param name="name">新的employee名称</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
//简单查询
Employee employee = GetEmployeeById(5);
if (employee != null)
{
Console.WriteLine("ID为5的员工已找到名称:" + employee.Em_Name);
}
//子查询
List<Employee> list_employees = GetEmployeesByPartId(1);
Console.WriteLine("共找到{0}记录:", list_employees.Count);
for (int i = 0; i < list_employees.Count; i++)
{
Console.Write(list_employees[i].Em_Name + ",");
}
/// <summary>
/// 根据ID查找EmpolyeeID 支持ADO语句和存储过程
/// </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 [email protected]", new { id = id }).FirstOrDefault();
}
//CommandDefinition command = new CommandDefinition("select * from employee wehre [email protected]");
//using (var conn = GetConnection())
//{
// employee = conn.Query<Employee>(command).FirstOrDefault();
//}
return employee;
}
/// <summary>
/// 子查询
/// </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 [email protected]) ", new { id = partid });
using (var conn = GetConnection())
{
employees = conn.Query<Employee>(command).ToList();
}
return employees;
}
时间： 2024-10-11 13:26:14