Oracle modifying fields and field types

Statement:
ALTER TABLE tableName Rename column oldcname to Newcname; --Modify field names
ALTER TABLE TableName Modify (cloumnname data type); --Modifying data types

For example:
1. Create a table:
CREATE TABLE Student (
ID VARCHAR2 (+) primary key,
Name VARCHAR2 (8) is not NULL,
Age Number
);
2. Modify the field name:
ALTER TABLE Student rename name to Stuname;
3. Modify the data type:
ALTER TABLE Student Modify (ID varchar2 (64));

Oracle modifying fields and field types