比较两个相似但不相同的数据表 [英] Compare two similar but not identical data tables

问题描述

我有两个数据表，它们有一个共同的主键列，但是不同的结构，因为它们是从不同的表创建的。我想检查数据表B中与A相比缺少哪些行，目的是将缺少的行添加到数据库中。

请查看这一个，它们提供了很好的答案，但是通常假定数据表是相同的。

由于我想获取插入的新行列表，有没有办法，我可以这样做而不迭代行和检查PK？如果我没有错，合并将保留旧行，我不想重新提交到数据库。

这两个表只有几十行，最多几百个。

编辑：这两个源表位于不同的数据库/服务器上，所以我不能轻易做SQL中的
比较。我更喜欢消费的应用程序，无论如何，我可以在完成之前添加一些更多的行处理。

解决方案

我希望我已经理解你的需求正确，但如何使用Linq？将2个表的键加载到2 IEnumerable< keytype> 对象中，例如（假设您的键是 int ）

  IEnumerable< int& keys1，keys2; 
 //将键加载到这些集合中的代码
 //查找keys2中keys2中缺少的keys2中的键：
 var missingKeys = keys1.Where（k1 =>！keys2。任何（k2 => k2 == k1））; 
  

HTH

I have two data tables which have a primary key column in common but otherwise different structures as they're created from different tables. I'd like to check which rows are missing from data table B compared to A, with the aim of adding in the missing rows to the database.

I've had a look at questions like this one, which provide good answers but the data tables are usually assumed to be the same.

Since I want to get a list of new rows for inserting, is there any way I can do this without iterating through the rows and checking the PKs? If I'm not mistaken, Merge will keep the old rows, which I don't want to resubmit to the database.

Both tables will have only a few dozen rows, a couple of hundred maximum. Would the computational hit of doing it row-by-row be negligible anyway?

edit: the two source tables are on different databases/servers, so I can't easily do the comparison in SQL. I'd prefer the consuming application to do it anyway, as I may add some more row processing before I'm done.

解决方案

I hope I've understood your needs correctly, but how about using Linq? Load the keys of your 2 tables into 2 IEnumerable<keytype> objects, e.g. (assuming your keys are of type int)

IEnumerable<int> keys1, keys2;
// code to load the keys into these collections
// to find the keys in keys1 that are missing from keys2:
var missingKeys = keys1.Where(k1 => !keys2.Any(k2 => k2 == k1)); 

HTH

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