Specifies the string to use for the null value, with a
maximum 4-byte UTF-8 string. The default is ‘NULL’.
You can specify a value such as a space (' ') or any string
up to four characters. Conceptually a field contains either a value
or an indication that there is no value. The system provides some
flexibility for how you indicate that a field contains no value.
The
system determines the type of a field and whether it is null by inspecting
the corresponding column declaration:
- If there is no value, the system sets the corresponding value
in the candidate binary record to null.
- If you declared the target column “not null,” then an absence
of a value is an error.
- If a field does not indicate null, the system assumes that it
contains a value. The system analyzes the contents of that field,
converts its textual input representation to binary, and sets the
corresponding value in the candidate binary record to that value.
IBM PureData System for Analytics, Version 7.1