如何比较c＃中的数据表 [英] How to compare datatables in c#

问题描述

Hi


我们正在为此示例导出2个不同数据库之间的数据：Teradata - > Cloudera。



我们需要的是确保每一行都被导出。



所以我使用C＃创建一个函数，从Teradata中提取数据并将其存储到DataTable中，其他函数从Cloudera中提取数据并将其存储到DataTable中。



我希望能够比较两个数据表并获取提取时是否缺少数据。



我尝试了什么：



我尝试合并两个数据表，迭代每一行，迭代for循环。但是需要花费大量时间来比较两个数据表

解决方案

DataTables没有用于复杂比较操作的内置方法，您需要自定义您的解决方案，可能是循环在嵌套的foreach循环中的两个DataTable上。

通过下面的代码片段查看它是否有效

  static   void  CompareRows（DataTable table1，DataTable table2）
 {
  foreach （DataRow row1  in  table1.Rows）
 {
  foreach  （DataRow row2  in  table2.Rows）
 {
  var  array1 = row1。 ItemArray; 
  var  array2 = row2.ItemArray; 
 
  if （array1.SequenceEqual（array2））
 {
 Console.WriteLine（ 等于：{0} {1}，
 row1 [   col1]，row2 [  col1 ]）; 
} 
  else  
 {
 Console.WriteLine（ 不相等：{0} {1}，
 row1 [  col1]，row2 [  col1] ）; 
} 
} 
} 

有很多方法可以比较数据。



最简单的方法是使用SQL工具在服务器端比较它们，请参阅：如何：比较和同步两个数据库的数据 [ ^ ]



最糟糕的解决方案是在客户端比较它们，特别是当数据库的大小很大时...

我建议你读这个：比较DataRows（LINQ to DataSet） [ ^ ]

Google图书： LINQ For Dummies - John Paul Mueller [ ^ ] br />
注意： Linq解决方案可能不是最好的选择，因为它的性能。因此，使用两个for循环可能比Linq解决方案更快。



决定属于你。

只计算每个数据表的行数，然后比较行数。

Hi
We are exporting data between 2 different databases for this example: Teradata -> Cloudera.

What we need is to make sure that every single row was exported.

So I create a function using C# that extract the data from Teradata and store it into a DataTable, other function that extract the data from Cloudera and store it into a DataTable.

I want to be able to compare both datatables and get if there is missing data on the extraction.

What I have tried:

I have tried merge both datatables, iterate for each row, iterate with for loop. But it take a lot of time to compare both datatables

解决方案

DataTables have no built-in methods for complicated comparison operations, You need to customize your solutions, may be loop over both DataTables in nested foreach-loops.
go through below snippet, see if it works

static void CompareRows(DataTable table1, DataTable table2)
    {
	foreach (DataRow row1 in table1.Rows)
	{
	    foreach (DataRow row2 in table2.Rows)
	    {
		var array1 = row1.ItemArray;
		var array2 = row2.ItemArray;

		if (array1.SequenceEqual(array2))
		{
		    Console.WriteLine("Equal: {0} {1}",
			row1["col1"], row2["col1"]);
		}
		else
		{
		    Console.WriteLine("Not equal: {0} {1}",
			row1["col1"], row2["col1"]);
		}
	    }
	}

There's numbers of ways to compare data.

The simplest way is to compare them on server's side using SQL tools, see: How to: Compare and Synchronize the Data of Two Databases[^]

The worst solution is to compare them on client's side, especially when the size of databases is large...
I'd suggest to read this: Comparing DataRows (LINQ to DataSet)[^]
Google book: LINQ For Dummies - John Paul Mueller[^]
Note: Linq solution may not be the best option, because of its performance. So, using two for-loops might be faster than Linq solution.

Decision belongs to you.

just count the number of rows of each datatable then compare number of rows.

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