A predicate is an expression that you configure to find a node in a hierarchical document. You can configure the expression to find a specific value. Create a predicate in an Input, Condition, or Output field of a mapping statement.
When you define a predicate, enclose the expression in square brackets [ ] after the node.
/<node>[expression]
For example, the following expression selects the book elements that are children of bookstore and have a price element with a value greater than 55.00:
/bookstore/book[price>55.00]
The following expression selects the title elements of the book elements that are children of bookstore with a price element value greater than 55.00:
/bookstore/book[price>55.00]/title
The following expression selects the title elements that have an attribute lang with a value of "eng":
//title[@lang="eng"]
The Data Processor transformation cannot accept all XPath statements in the Output field when you configure a mapping statement with the Add mode or the Match or Add mode.