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.
Though shaken, Oppenheimer continued to direct the Institute for Advanced Study and to write on the relation of Western culture to science. He bought a house in the Virgin Islands and spent time sailing. In 1963 the AEC conferred on him the Enrico Fermi Award. In 1966 he resigned from the institute.