TParameterMap holds one or more parameter child elements that map object
properties to placeholders in a SQL statement.
A TParameterMap defines an ordered list of values that match up with the
placeholders of a parameterized query statement. While the attributes
specified by the map still need to be in the correct order, each parameter
is named. You can populate the underlying class in any order, and the
TParameterMap ensures each value is passed in the correct order.
Parameter Maps can be provided as an external element and inline.
The element accepts two attributes: id (required) and extends (optional).