CODEWITHSUNDEEP
xquerysequencenodes
Ben Aston
Ben Aston

Reputation: 55759

XQuery - are strings implicit nodes?

e.g.

Is it accurate to describe the folowing as a sequence of text nodes?

("foo", "bar", "baz")

Upvotes: 0

Views: 82

Answers (1)

Jens Erat
Jens Erat

Reputation: 38712

No, they aren't. Strings are not equal to text nodes, this is a sequence of strings.

Text nodes are of type Node, which again is an item (these are the most general data type in XQuery). Strings are derived from xs:anyAtomicType, which again is also an item.

Have a look at XQuery's data type diagram.

Determining the Type of an Item

A sequence of text nodes could be constructed using

(text { "foo" }, text { "bar" }, text { "baz" })

You can easily determine the type of a node using the typeswitch construct:

for $item in (text { "foo" }, "bar", 42)
return
  typeswitch($item)
    case text()
      return "text node"
    case xs:string
      return "string"
    default
      return "Something else"

Inherited Types

You can also test for inherited types:

for $item in (text { "foo" }, "bar", 42)
return
  typeswitch($item)
    case node()
      return "node"
    case xs:anyAtomicType
      return "anyAtomicType"
    default
      return "Something else"

Upvotes: 3

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