Oracle----Key Word

desc|describe table_name

DCL----column

----add

-- add one column
alter table product
add state varchar2(10);

-- add multiple columns
alter table product
add (state varchar2(2) default '', names varchar2(100), age number);

----drop

-- drop one column
alter table product
drop column name;

-- drop multiple columns
alter table product
drop (names, state);

----modify

-- modify one column
alter table product
modify address date;

-- modify multiple columns
alter table product
modify (age varchar2(20), address int, mail date);