xs:ID

Construct an ID value from an item value.

Related Syntax Constructs

The following construct(s) refer to this construct:

[ Syntax | Description | Argument | Example ]

Syntax

xs:ID(item $value) => ID

Description

This is a constructor function that takes an item value as argument and returns a value of type xs:ID. If the argument is a literal, then the literal must be a valid lexical form of its type.

As specified in the respective section of the W3C recommendation XML Schema Part 2: Datatypes, a value of type xs:ID denotes an ID attribute type, as defined in the XML 1.0 recommendation. It is derived from the type xs:NCName and the lexical form of xs:ID is the set of all strings that match the production of NCName.

For compatibility reasons values of this type should only be used as attribute values.

Argument

$value	item value

Example

The following queries generate valid values of type xs:ID
```
xs:ID("_header")
```
```
xs:ID("R2D2")
```
The following queries generate invalid values of type xs:ID
```
xs:ID("-header")
```
```
xs:ID("1A")
```