DTD到底是什么？ [英] What is DTD exactly?

问题描述

我在文档中多次使用DTD，但是我不知道它的重要性。我还试图理解 DTD的W3Schools教程。但是我觉得它太理论化了。

I have used DTD several times in my document, but I never knew its significance. I have also tried to understand W3Schools tutorial of DTD. But I found it too theoretical.

确切地说，DTD的意义是什么，为什么类型定义如此重要？

What is the significance of DTD exactly, and why are type definitions are so important?

推荐答案

认为它有点像数据库的架构-我们已经习惯了在普通关系数据库中只能使用已经声明的列的想法，并且您必须在其中插入正确的数据。好吧，DTD对XML文档的处理大致相同。

Think of it as being a bit like a schema for a database - we're used to the idea that in normal relational databases you can only use columns which have already been declared, and you have to insert the right kind of data in them. Well, a DTD does roughly the same kind of thing for XML documents.

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