C# 哪个更好：DataSet 或 DataReader？

What's better: DataSet or DataReader?

提问by Daniel

I just saw this topic: Datatable vs Datasetbut it didn't solve my doubt .. Let me explain better, I was doing connection with database and needed to show the results in a GridView. (I used RecordSet when I worked with VB6 while ago and DataSet is pretty similar to it so was much easier to use DataSet.) Then a guy told me DataSet wasn't the best method to do ..

我刚看到这个话题：Datatable vs Dataset但它并没有解决我的疑问..让我解释得更好，我正在与数据库进行连接，需要在 GridView 中显示结果。（我之前在使用 VB6 时使用了 RecordSet，而 DataSet 与它非常相似，因此使用 DataSet 更容易。）然后一个人告诉我 DataSet 不是最好的方法。

So, should I 'learn' DataReader or keep using DataSet ? DataTable ? What are the pros/cons ?

那么，我应该“学习” DataReader 还是继续使用 DataSet ？数据表？有什么优点/缺点？

采纳答案by Marc Gravell

That is essentially: "which is better: a bucket or a hose?"

这基本上是：“哪个更好：水桶还是软管？”

A DataSetis the bucket here; it allows you to carry around a disconnected set of data and work with it - but you will incur the cost of carrying the bucket (so best to keep it to a size you are comfortable with).

ADataSet是这里的桶；它允许您携带一组断开连接的数据并使用它 - 但您将承担携带存储桶的费用（因此最好将其保持在您满意的大小）。

A data-reader is the hose: it provides one-way/once-only access to data as it flies past you; you don't have to carry all of the available water at once, but it needs to be connected to the tap/database.

数据读取器是软管：当数据从您身边飞过时，它提供对数据的单向/一次性访问；您不必一次携带所有可用的水，但需要将其连接到水龙头/数据库。

And in the same way that you can fill a bucket with a hose, you can fill the DataSetwith the data-reader.

就像你可以用软管装满水桶一样，你也可以DataSet用数据读取器装满水桶。

The point I'm trying to make is that they do different things...

我想说明的一点是他们做不同的事情......

I don't personally use DataSetvery often - but some people love them. I do, however, make use of data-readers for BLOB access etc.

我个人不DataSet经常使用- 但有些人喜欢它们。但是，我确实使用数据读取器进行 BLOB 访问等。

回答by Ahmad Mageed

It depends on your needs. One of the most important differences is that a DataReader will retain an open connection to your database until you're done with it while a DataSet will be an in-memory object. If you bind a control to a DataReader then it's still open. In addition, a DataReader is a forward only approach to reading data that can't be manipulated. With a DataSet you can move back and forth and manipulate the data as you see fit.

这取决于您的需求。最重要的区别之一是 DataReader 将保留与您的数据库的打开连接，直到您完成它，而 DataSet 将是内存中的对象。如果您将控件绑定到 DataReader，则它仍处于打开状态。此外，DataReader 是一种仅向前读取无法操作的数据的方法。使用 DataSet，您可以来回移动并按照您认为合适的方式操作数据。

Some additional features: DataSets can be serialized and represented in XML and, therefore, easily passed around to other tiers. DataReaders can't be serialized.

一些附加功能： 数据集可以序列化并以 XML 表示，因此可以轻松地传递到其他层。DataReaders 不能被序列化。

On the other hand if you have a large amount of rows to read from the database that you hand off to some process for a business rule a DataReader may make more sense rather than loading a DataSet with all the rows, taking up memory and possibly affecting scalability.

另一方面，如果您有大量要从数据库中读取的行，您将这些行交给某个业务规则的某个进程，那么 DataReader 可能更有意义，而不是加载包含所有行的 DataSet、占用内存并可能影响可扩展性。

Here's a link that's a little dated but still useful: Contrasting the ADO.NET DataReader and DataSet.

这是一个有点过时但仍然有用的链接：对比 ADO.NET DataReader 和 DataSet。

回答by AviD

Different needs, different solutions.

不同的需求，不同的解决方案。

As you said, dataset is most similar to VB6 Recordset. That is, pull down the data you need, pass it around, do with it what you will. Oh, and then eventually get rid of it when you're done.

正如您所说，数据集与 VB6 Recordset 最相似。也就是说，拉下你需要的数据，传递它，做你想做的。哦，然后在你完成后最终摆脱它。

Datareader is more limited, but it gives MUCH better performance when all you need is to read through the data once. For instance, if you're filling a grid yourself - i.e. pull the data, run through it, for each row populate the grid, then throw out the data - datareader is much better than dataset. On the other hand, dont even try using datareader if you have any intention of updating the data...

Datareader 受到更多限制，但是当您只需要读取一次数据时，它可以提供更好的性能。例如，如果您自己填充网格 - 即提取数据，遍历它，为每一行填充网格，然后丢弃数据 - datareader 比数据集好得多。另一方面，如果您有任何更新数据的意图，甚至不要尝试使用 datareader ...

So, yes, learn it - but only use it when appropriate. Dataset gives you much more flexibility.

所以，是的，学习它 - 但只在适当的时候使用它。数据集为您提供了更大的灵活性。

回答by Martin Clarke

To answer your second question - Yes, you should learn about DataReaders. If anything, so you understand how to use them.

要回答您的第二个问题 - 是的，您应该了解 DataReaders。如果有的话，那么您就了解如何使用它们。

I think you're better of in this situation using DataSets - since you're doing data binding and all (I'm thinking CPU cycles vs Human effort).

我认为在这种情况下使用 DataSet 会更好 - 因为您正在进行数据绑定和所有操作（我在考虑 CPU 周期与人工工作）。

As to which one will give a better performance. It very much depends on your situation. For example, if you're editing the data you're binding and batching up the changes then you will be better off with DataSets

至于哪一个会给出更好的表现。这在很大程度上取决于您的情况。例如，如果您正在编辑要绑定的数据并对更改进行批处理，那么使用 DataSet 会更好

回答by John Saunders

Further to Marc'spoint: you can use a DataSet with no database at all.

进一步Marc 的观点：您可以使用根本没有数据库的 DataSet。

You can fill it from an XML file, or just from a program. Fill it with rows from one database, then turn around and write it out to a different database.

您可以从 XML 文件或仅从程序中填充它。用一个数据库中的行填充它，然后转身将其写出到另一个数据库。

A DataSet is a totally in-memory representation of a relational schema. Whether or not you ever use it with an actual relational database is up to you.

数据集是关系模式的完全内存表示。您是否曾经将它与实际的关系数据库一起使用取决于您。

回答by siddu patil

DataReader vs Dataset

数据阅读器与数据集

1) - DataReader is designed in the connection-oriented architecture
- DataSet is designed in the disconnected architecture

1) - DataReader 是在面​​向连接的架构中设计的
- DataSet 是在断开连接的架构中设计的

2) - DataReader gives forward-only access to the data
- DataSet gives scrollable navigation to the data

2) - DataReader 提供对数据的只进访问
- DataSet 提供对数据的可滚动导航

3) - DataReader is read-only we can't make changes to the data present under it
- DataSet is updatable we can make changes to the data present under it and send those changes back to the data source

3) - DataReader 是只读的，我们不能对其下的数据进行更改
- DataSet 是可更新的，我们可以对其下的数据进行更改并将这些更改发送回数据源

4) - DataReader does not provide options like searching and sorting of data
- DataSet provides options like searching and sorting of data

4) - DataReader 不提供数据搜索和排序等
选项 - DataSet 提供数据搜索和排序等选项