Dropping a column

You can drop a column by using the ALTER TABLE statement with a DROP COLUMN clause. Only one DROP COLUMN clause is supported in an ALTER TABLE statement. To drop multiple columns, use multiple ALTER TABLE statements.

When you drop a column, this can produce a range of undefined space in the table if there are no other columns that map the same space. IMS does not shift the remaining columns together. Any subsequent ADD COLUMN clauses will, by default, add the new columns at towards the end of the table after the last column. You may optionally specify an ADD COLUMN, defining a new column in the space of the previous one you dropped by specifying the START keyword on the clause.