Transaction Script(事务脚本模式),是一种最简单和最容易接受的处理业务的方法。这种模式是采用面向过程的方式来组织业务逻辑。通常情况下，系统的一个流程会被实现为一个方法，然后所有的方法被组织在一起，放在一个类中。
设计思想：取数据-》逻辑-》数据展示。 存数据-》逻辑-》保存数据。
优点
- 简单，对大多数开发者都可用理解
- 一个事务的处理，不会影响到其他的事务
缺点
业务逻辑复杂时，系统每增加一个业务流程，代码就会增加一个或几个方法，最后业务类中存在大量相似的代码（重用性不强，难以维护）
案例
人事管理系统中的请假流程
- 判断员工提交的请假数据是否合法
- 检查提交请求的员工是否还有剩余假期
- 批准假期，并记录下来
Code
一般解决通过sql查询数据，在将查询结果赋值给交换对象。代码下载
交换数据类
/// <summary>
/// 请假申请数据交换对象
/// </summary>
public class BookedLeaveDTO
{
public DateTime From { get; set; }
public DateTime To { get; set; }
public int DaysTaken { get; set; }
}
/// <summary>
/// 员工数据对象
/// </summary>
public class EmployeeDTO
{
public int Id { get; set; }
public string Name { get; set; }
public int HolidayEntitlement { get; set; }
}
服务对象
public class EmployeeService
{
private static string connectionString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
/// <summary>
/// 添加员工
/// </summary>
/// <param name="name"></param>
/// <param name="holidayEntitlement"></param>
public static void CreateEmployee(string name, int holidayEntitlement)
{
string insertSql = "INSERT INTO Employees " +
"(Name, HolidayEntitlement) VALUES " +
"(@Name, @HolidayEntitlement); SELECT @@identity;";
using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlCommand command = connection.CreateCommand();
command.CommandText = insertSql;
command.Parameters.Add(new SqlParameter("@Name", name));
command.Parameters.Add(new SqlParameter("@HolidayEntitlement", holidayEntitlement));
connection.Open();
command.ExecuteNonQuery();
}
}
/// <summary>
/// 得到公司所有员工
/// </summary>
/// <returns></returns>
public static List<EmployeeDTO> GetAllEmployees()
{
List<EmployeeDTO> employees = new List<EmployeeDTO>();
string selectSql = "SELECT * FROM Employees;";
using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlCommand command = connection.CreateCommand();
command.CommandText = selectSql;
connection.Open();
using (SqlDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
employees.Add(new EmployeeDTO
{
Id = int.Parse(reader["Id"].ToString()),
Name = reader["Name"].ToString(),
HolidayEntitlement = int.Parse(reader["HolidayEntitlement"].ToString())
});
}
}
}
return employees;
}
}
public class HolidayService
{
private static string connectionString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
/// <summary>
/// 员工请假
/// </summary>
/// <param name="employeeId"></param>
/// <param name="From"></param>
/// <param name="To"></param>
/// <returns></returns>
public static bool BookHolidayFor(int employeeId, DateTime From, DateTime To)
{
bool booked = false;
TimeSpan numberOfDaysRequestedForHoliday = To - From;
if (numberOfDaysRequestedForHoliday.Days > 0)
{
if (RequestHolidayDoesNotClashWithExistingHoliday(employeeId, From, To))
{
int holidayAvailable = GetHolidayRemainingFor(employeeId);
if (holidayAvailable >= numberOfDaysRequestedForHoliday.Days)
{
SumitHolidayBookingFor(employeeId, From, To);
booked = true;
}
}
}
return booked;
}
/// <summary>
/// 请假日期是否于法定假日冲突
/// </summary>
/// <param name="employeeId"></param>
/// <param name="From"></param>
/// <param name="To"></param>
/// <returns></returns>
private static bool RequestHolidayDoesNotClashWithExistingHoliday(int employeeId, DateTime From, DateTime To)
{
return true;
}
/// <summary>
/// 剩余假期数
/// </summary>
/// <param name="employeeId"></param>
/// <returns></returns>
private static int GetHolidayRemainingFor(int employeeId)
{
List<BookedLeaveDTO> bookedLeave = GetBookedLeaveFor(employeeId);
int daysTaken = bookedLeave.Sum(hol => hol.DaysTaken);
int holidayEntitlement = GetHolidayEntitlementFor(employeeId);
int daysRemaining = holidayEntitlement - daysTaken;
return daysRemaining;
}
/// <summary>
/// 期间内请假的所有员工
/// </summary>
/// <param name="From"></param>
/// <param name="To"></param>
/// <returns></returns>
public static List<EmployeeDTO> GetAllEmployeesOnLeaveBetween(DateTime From, DateTime To)
{
// ... Example of Transaction Script Method ...
throw new NotImplementedException();
}
/// <summary>
/// 所有员工假期剩余天数
/// </summary>
/// <returns></returns>
public static List<EmployeeDTO> GetAllEmployeesWithHolidayRemaing()
{
// ... Example of Transaction Script Method ...
throw new NotImplementedException();
}
/// <summary>
/// 批准请假
/// </summary>
/// <param name="employeeId"></param>
/// <param name="From"></param>
/// <param name="To"></param>
private static void SumitHolidayBookingFor(int employeeId, DateTime From, DateTime To)
{
string insertSql = "INSERT INTO Holidays (EmployeeId, LeaveFrom, LeaveTo) VALUES " +
"(@EmployeeId, @LeaveFrom, @LeaveTo);";
using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlCommand command = connection.CreateCommand();
command.CommandText = insertSql;
command.Parameters.Add(new SqlParameter("@EmployeeId", employeeId));
command.Parameters.Add(new SqlParameter("@LeaveFrom", From));
command.Parameters.Add(new SqlParameter("@LeaveTo", To));
connection.Open();
command.ExecuteNonQuery();
}
}
/// <summary>
/// 员工所请的假期
/// </summary>
/// <param name="employeeId"></param>
/// <returns></returns>
public static List<BookedLeaveDTO> GetBookedLeaveFor(int employeeId)
{
List<BookedLeaveDTO> bookedLeave = new List<BookedLeaveDTO>();
string selectSql = "SELECT * FROM Holidays WHERE EmployeeId = @EmployeeId;";
using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlCommand command = connection.CreateCommand();
command.CommandText = selectSql;
command.Parameters.Add(new SqlParameter("@EmployeeId", employeeId));
connection.Open();
using (SqlDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
bookedLeave.Add(new BookedLeaveDTO
{
From = DateTime.Parse(reader["LeaveFrom"].ToString()),
To = DateTime.Parse(reader["LeaveTo"].ToString()),
DaysTaken = ((TimeSpan)(DateTime.Parse(reader["LeaveTo"].ToString()) - DateTime.Parse(reader["LeaveFrom"].ToString()))).Days
});
}
}
}
return bookedLeave;
}
/// <summary>
/// 员工剩余假期
/// </summary>
/// <param name="employeeId"></param>
/// <returns></returns>
private static int GetHolidayEntitlementFor(int employeeId)
{
string selectSql = "SELECT HolidayEntitlement FROM Employees WHERE Id = @EmployeeId;";
int holidayEntitlement = 0;
using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlCommand command = connection.CreateCommand();
command.CommandText = selectSql;
command.Parameters.Add(new SqlParameter("@EmployeeId", employeeId));
connection.Open();
holidayEntitlement = int.Parse(command.ExecuteScalar().ToString());
}
return holidayEntitlement;
}
}