OE1-5.3 XML & JSON

Work through these

• Introduction to XML and its uses

  A general way of marking up structured data, and why anyone wanted one. Its main use now is in configuration and in older systems, which is worth saying plainly.

• The syntax of XML

  The rules a document must obey to be readable at all. Being strict is the whole point: a parser refuses rather than guessing.

• XML document structure

  How a document is organised, from the declaration to the single root. It is short and it prevents a lot of confusion.

• Namespaces and why they exist

  Avoiding name collisions when two vocabularies are combined. It is the item that looks like bureaucracy and turns out to be necessary.

• XML schemas

  Declaring what a valid document looks like, so it can be checked automatically. Validation is the strongest argument for this format over the alternative below.

• Displaying raw XML documents

  What a browser does with a document that has no styling. It shows the structure, which is a useful debugging habit.

• Displaying XML documents with CSS

  Applying the styling from the first topic to structured data. It demonstrates the separation of content from presentation in a second setting.

• JSON

  The lighter alternative, which is what almost every modern interface actually uses. Its mapping onto the language's own data types is why it won.

• XML versus JSON

  The comparison, which is the item the topic exists for. One validates and describes; the other is compact and immediate, and knowing when each is right is the takeaway.