ALTER Command (DDL) in SQL Oracle with Implementation on ORACLE For Explanation Watch video: 1)Alter Modify :: to modify column name or datatype EX:: SQL> create table emp01(name char(10),sal Number(10)); Table created. SQL> desc emp01; Name Null? Type ----------------------------------------- -------- ---------------------------- NAME CHAR(10) SAL NUMBER(10) SQL> alter table emp01 modify name varchar2(10); Table altered. SQL> desc Emp01; Name Null? Type ----------------------------------------- -------- ---------------------------- NAME VARCHAR2(10) SAL NUMBER(10) SQL> alter table emp01 modify name varchar2(15)/*to change the size of varchar2*/; Table altered. SQL> desc emp01; Name