PL/SQL :: Populate Target Table - Dynamic Rows

create table src(id number,val number,data varchar2(100)) insert into src values (1,1,'SUN');
insert into src values (2,2,'WED');
insert into src values (3,3,'MON');     
create table trg(id number,val number,data varchar2(100)) required rows to be inserted in the target table. 

  insert into trg values (1,1,'SUNDAY');
insert into trg values (2,0,NULL);
insert into trg values (2,0,NULL);
insert into trg values (3,0,NULL);
insert into trg values (3,0,NULL);insert into trg values (3,0,NULL); 

 {code} based on the column value  of the source table src's column val , i need to populate my target table trg . If the value of val is 1 then  only one target row is created in the target .If the value of val in the source table src is 2 then the target is populated with 2 rows .The values of the target columns are mapped as follow:

1)id -as it is

2)val - if the val of src is 1 then map the val as it is .If the value of val is more than one then create as many rows as the value of val ,id will be as it is and the  value of val and data will be null

3)data - if the val of src is 1 then expand the abbreviation else null .