使用EntityFramework时，DB2的Timestamp数据不准确 [英] Timestamp data from DB2 is not accurate when using EntityFramework

问题描述

我在IBM DB2中有数据，而我想要做的是使用EntityFramework获取数据。
我有一列具有以下格式的TIMESTAMP值：dd.MM.yyyy hh：mm：ss.ffffff，它是该表中的主键。

当我从DB2数据库获取数据时间戳的时间部分丢失。
另一方面，我有一个具有该字符串属性的实体：

  public string Id {get;组; } 
  

这是一种返回特定商家的方法。预计只有一个，因为名称Ids的时间戳是唯一的。但是，当数据被拉扯并且时间部分丢失时，我得到9个商家具有相同的Id，当然例外）。

 商家实体IMerchantRepository.GetMerchantByRegistrationNumber（string companyRegistrationNumber）
 {
 var db = merchantDataContextProvider.GetMerchantContext（）; 
 var merchant = db.Merchants.Include（x => x.MerchantProperty）。 
 SingleOrDefault（x => x.MerchantProperty.CompanyRegistrationNumber == companyRegistrationNumber）; 
返回商家
} 
  

我试图使用DateTime类型为Id，唯一的区别是它正在切割最后3个数字，而不是整个时间部分。

有没有人有相同或类似的问题？谁在使用DB2时获得准确的数据？

解决方案

时间戳作为主要的关键..不是一个好主意。不过，如果您希望使用时间作为创建商家ID的依据，可以这样做：

  var newId = string.format（{0：D19}，DateTime.Now.Ticks）
  

根据当前时间给您一个19位数的长号码。当然问题在于，如果PC上的时钟复位，或者在不同的计算机上运行程序，不同的时区等，这个策略就会失败。

如果您需要在表格中唯一标识行的内容，请使用GUID。他们是非常独特的，两个不同的过程使得同一个进程的机会非常接近零

I have data in IBM DB2 and what I am trying to do is to get that data using EntityFramework. I have one column that has TIMESTAMP values in this format: dd.MM.yyyy hh:mm:ss.ffffff and it is primary key in that table.

When I am getting data from DB2 database time part of timestamp is lost. On the other side I have entity that has string property for that Id:

public string Id { get; set; }

This is a method that will return specific merchant. It is expected only one, because timestamps aka Ids are unique. But, when data gets pulled and when time part is lost I get 9 merchants with same Id and of course exception).

MerchantEntity IMerchantRepository.GetMerchantByRegistrationNumber(string companyRegistrationNumber)
{
     var db = merchantDataContextProvider.GetMerchantContext();
     var merchant = db.Merchants.Include(x => x.MerchantProperty).
         SingleOrDefault(x => x.MerchantProperty.CompanyRegistrationNumber == companyRegistrationNumber);
     return merchant;
}

I have tried to use DateTime type for Id, the only difference was that it was cutting last 3 numbers, instead whole time part.

Did anyone had same or similar problem? Who to get accurate data when using DB2?

解决方案

Timestamps as primary key.. not a great idea. If you do however want to use time as your basis for creating an ID of the merchant, you could do this:

var newId = string.format("{0:D19}", DateTime.Now.Ticks)

which will give you a 19-digit long number based on the current time. The problem of course is that if the clock on the PC resets, or you run the program on a different computer, different timezones etc, this strategy will fail.

If you need something that uniquely identifies a row in a table, use GUID's. They're very unique, and the chance of two different processes making the same one is very close to zero

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