Using field-level sensitivity with variable-length segments

When field-level sensitivity is used with a variable-length segment, an application program's view of the segment is fixed in length and does not include the 2-byte length field.

This topic and its subtopics address special situations when field level sensitivity is used with variable-length segments. First, however, here is some general information about using field-level sensitivity with variable-length segments:

• When inserting a variable-length segment, the length used is the minimum length needed to hold all sensitive fields.
• When replacing a variable-length segment, if the length has to be increased to contain data an application program has modified, the length used is the minimum length needed to hold the modified data.
• An application program cannot be sensitive to overlapping fields in a variable-length segment with get or update sensitivity if the data type of any of those fields is not character.
• Existing programs processing variable-length segments that use the length field to determine the presence or absence of a field might need to be modified if segments are inserted or updated by programs using field-level sensitivity.

When field-level sensitivity is used with variable-length segments, two situations exist that you should know about. The first is when fields are missing. The second is when fields are partially present. This topic examines the following information:

• Retrieving Missing Fields
• Replacing Missing Fields
• Inserting Missing Fields
• Retrieving Partially Present Fields
• Replacing Partially Present Fields