Oracle provides alter table syntax to modify data columns in-place in this form: alter table table_name modify column_name datatype; If you are brave you can use a single alter table syntax to modify multiple columns:
PRINCETON, N. J., Feb. 18--Dr. J. Robert Oppenheimer, the nuclear physicist, died here tonight at the age of 62. A spokesman for the family said Dr. Oppenheimer died at 8 o'clock in his home on the grounds of the Institute for Advanced Study. He had been ailing since early last year with cancer of the throat.
John Dalton (1766-1844) was an English scientist who made his living as a teacher in Manchester. He is best known for his atomic theory. John Dalton was aware of these observations and in about 1808 he offered an explanation for them that became known as Dalton's atomic theory.