This is something so simple, yet can cause you to pull your hair out. All you want to do is alter the length of a column in an Oracle table:
An example table:
Members
MbrID number(5)
FirstName varchar2(30)
Surname varchar2(30)
Now you wish to increase the length of the surname to 50 characters, as someone has a longer than usual surname.
Here is the syntax to do this:
alter table members
modify surname varchar2(50)
This has now been updated to :
Members
MbrID char(5)
FirstName varchar2(30)
Surname varchar2(50)
When you wish to add a column:
alter table members
add DateOfBirth date
When you wish to remove a column:
alter table members
drop column DateOfBirth
When you wish to rename a column
alter table customers
rename column surname to lastname
