A field which has been previously defined in the screen layout of a map
may be assigned the field name and field attributes of a DDM field definition
or a DEFINE DATA definition.
Note:
Duplicate field names are only allowed for fields defined as
output-only fields.
A map field which has been created from a DDM can be redefined by using
the appropriate DDM field definition from this DDM or a DEFINE
DATA definition.
Post assignment can be done by entering the number (or letter) assigned to a DDM field definition as described in Selecting Data Definitions.
Post assignment can only be done if the format of the layout agrees with
the field definition. N and P are considered to be
identical numeric.
Post assignment cannot be used for view arrays (in a DDM field definition
or a DEFINE DATA definition) if one or more
dimensions of that array are smaller than the dimensions of the array in the
layout.
If a length conflict occurs, an AL/FL/NL attribute is generated to map the field definition to the layout definition with truncation or expansion. Data is truncated when AL/FL/NL is specified.