Key Fields - (PROCOPT=K)

► Used to sequence the database and can't be changed

► It’s the field within a segment, used to identify the occurrence of the segment

► used to maintain the IMS segments in ascending sequence.

Search Fields - (PROCOPT=G)

► Used to search for a segment, without the segment being sequenced on that field

► A segment need not have a key or search field.

Both types of fields can be used to search the database.