NetMaster Database Administration › Alter Field Definitions in an NDB › Delete Field Definitions

Delete Field Definitions

Deleting a field definition logically removes the field from the database. Following the delete, all data values for that field become inaccessible.

Deleting a field immediately makes the field inaccessible to NCL procedures. Any currently active sequences (&NDBSEQ) defined on that field, if it is keyed, are given a response code on the next &NDBGET referring to that sequence. Predefined formats (&NDBFMT) referring to the field still valid until they are redefined. An in-progress &NDBSCAN could get undefined results.

Deleting a field causes a physical VSAM delete to be performed for all the associated key records. The data records, however, are not updated. To do so would create an unacceptable overhead. Instead, the field value in each data record is regarded as logically deleted. It is inaccessible. Whenever a data record is updated, all logically deleted fields are removed.