In Chapter 4, we provided a brief discussion of several types of metadata. In this chapter, you’ll read more about structural metadata. In particular, you’ll learn what Document Type Definitions (or DTDs) are and how they add value to XML documents, about XML Schema and the additional values that it provides, and about other structural metadata specification languages.
You’ll recall that Chapter 4 described structural metadata thusly: Structural metadata is metadata that describes the structure, type, and relationships of data. In this chapter, we explore how each of those aspects of data – its structures, its types, and its relationships – can be specified for XML documents. We also discuss how ...