Item references return the values of input data and variables.
The format of item references used by condition expressions is shown below.
The format of item references used by join-relational expressions, output items of output expressions, and lookup functions is shown below.
Note
If an item reference that does not exist is specified
If an item reference that does not exist is specified in a search expression, join-relational expression, or similar, it is processed as having a "null" value.
See
Refer to "2.4.1 Item Expressions" for details.
Refer to "2.4.2 Path Expressions" for details.
Refer to "2.4.3 Text Expressions" for details.
Refer to "2.4.4 Attribute Expressions" for details.
