Data Transformation Engine Type Designer Reference Guide

Chapter 12 - Error Detection and Recovery Error Detection
Function Description
EXISTS
Something in the data represents that data object.
CONTENT
The data contains at least one byte other than a syntactical
placeholder, such as a pad character or delimiter.
PRESENT
The data object exists and has content.
ABSENT
The data object does not exist or it exists and has no content.
Required components must exist. They do not necessarily have to be present. For
example, a required item with no minimum content size can exist, be absent, and
still be valid. However, if some minimum content size is specified, a required
component is not valid if there is no minimum content.
The existence of optional components depends on the context in which they are
used. For example:
♦ In a delimited group, an optional component must exist if data follows.
♦ In a fixed group, an optional component must exist if trailing white space is
required. If no trailing white space is required, an optional component must
exist if data follows.
♦ In an implicit group, an optional component is not required.
Unlike a required component, when an optional component exists, it may have no
content - even when the minimum content specification is greater than zero bytes.
The following table explains the conditions that must be met for required and
optional components:
EXISTS CONTENT PRESENT ABSENT
Required
Component
Must exist in
any context
Must conform
to content
specification
Must be
present if
minimum
content
specification
is greater
than zero
bytes.
May be absent
only if minimum
content
specification is
zero.
Optional
Component
Depends on
context
Need not have
content
Not necessary May be absent