7. Writing Field-developed Applications › 7.5 MSI Definition Notes › 7.5.7 KEEP and DROP Processing

7.5.7 KEEP and DROP Processing

The FDA definition using MSI is simplified through the use of
new statements.

The KEEP and DROP statements control whether or not a data
element is active.

The following rules apply to KEEP/DROP processing:

   o If no KEEP/DROP statement is specified, then the default
     action is to KEEP.

   o Once a KEEP statement is encountered, the default action
     is to DROP.

   o Sequence Elements cannot be dropped.

   o KEEP and DROP specified for individual timespans
     override Global Definitions.

   o Dropping a data element in Detail also drops in Days,
     Weeks, Months, and Years.