了解数据外劳务：SOA [英] Understanding Data Outside Of Service : SOA

问题描述

注：服务之外的数据是指由客户服务返回和使用的消息

。

我有一个名为LastBuyer服务服务。这将返回一本书的最后买主的名字，当我输入BOOKID的服务。当我呼吁相同的书籍ID服务，它会返回不同的结果（如果一本书是由新买家购买）。因此，我不能缓存在客户端服务（为特定的BookID）的结果。

在阅读文章数据在里面对数据在外面它说：好了，以高速缓存 - 由于消息的ID返回相同的数据，这是确定缓存消息

参考： http://msdn.microsoft.com/en-us/库/ ms954587.aspx

1. 什么是缺少点在我的理解？

2. 在消息不可变的，上面的例子？

3. 什么是在上面的例子中版本依赖性和版本无关的标识？

4. 如何在消息的版本在这里做什么？

5. 这是WCF的书，介绍了SOA概念和模式显然与例子？

阅读

1. 在服务设计的原则：服务模式和反模式

http://msdn.microsoft.com/en-us/library/ ms954638.aspx

解决方案

1. 您缺少的（如@卡斯滕 - 柯尼希暗示）的事实，数据的对于任何给定的快照时间的是不可改变的。除非你回去填补旧订单，然后最后一个人买的书5:00昨天下午总是将是相同的。自那之后有人买了这本书（造成新的版本的数据）的事实是无关紧要昨天的结果。这可能是也可能不是有用的数据高速缓存，但由于在任何特定的时间点的它是不可变的。

2. 该消息是不可变的，如果该消息的主要组成部分是它的时间戳。

3. 该版本无关的标识是书的编号。该版本相关的标识符是快照时间戳。

4. 通过快照时间戳（这再次，可能会或不会对缓存的目的是有用的）

作为一本好书，关于这个问题，我怕我不能给出建议。但我怀疑，在亚马逊的评论或bn.com是一个良好的开端。

Note: Data outside of service means the message returned by a service and consumed by the client.

I have a service named LastBuyer Service. This will return the last buyer name of a book when I input the bookID to the service. When I call the service for the same book id, it will return different result (if a book is purchased by a new buyer). So I cannot cache the result of the service in the client (for a particular BookID).

While reading the article "Data on the Inside vs. Data on the Outside" it says "Ok to Cache" – " Since the ID of the message returns the same data, it is OK to cache a message".

Reference: http://msdn.microsoft.com/en-us/library/ms954587.aspx

1. What is the missing point in my understanding?

2. Is the message immutable in above example?

3. What are the version-dependent and version-independent identifiers in above example?

4. How is versioning of message done here?

5. Which is the WCF book that explains SOA concepts and patterns clearly with examples?

READING

1. Principles of Service Design: Service Patterns and Anti-Patterns

http://msdn.microsoft.com/en-us/library/ms954638.aspx

解决方案

1. You are missing the fact that (as @Carsten-Konig implies) the data for any given snapshot time is immutable. Unless you go back and fill in old orders, then the last person to buy the book as of 5:00 PM yesterday is always going to be the same. The fact that since then someone has bought the book (resulting in a new version of that data) is irrelevant to yesterday's result. This may or may not be useful data to cache, but as of any given point in time it is immutable.

2. The message is immutable if part of the message's key is it's timestamp.

3. The version-independent identifier is the ID of the book. The version-dependent identifier is the snapshot timestamp.

4. By snapshot timestamp (which again, may or not be useful for caching purposes)

As for a good book on the subject, I'm afraid I can't give recommendations. But I suspect that the reviews on amazon or bn.com are a good place to start.

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