update float column from varchar2

 Hi,

I want to update my new column added in table with varchar2 column.. 

I have the below table.

desc MY_TABLE1

Name Null Type         

---- ---- ------------ 

ID        VARCHAR2(20) 

select * from MY_TABLE1;

ID                 

--------------------

123456789.123456789  

123456789.123456789  

123456789.123456789  

3 rows. 

now add one new column in same table as below. 

alter table MY_TABLE1 add (id_migration FLOAT);

desc MY_TABLE1

Name         Null Type         

------------ ---- ------------ 

ID                VARCHAR2(20) 

ID_MIGRATION      FLOAT(126)   

select * from MY_TABLE1;

D                   ID_MIGRATION

-------------------- ------------

123456789.123456789               

123456789.123456789               

123456789.123456789          

when i update float column from varchar2, it is not update after dot(.) charcter..

update MY_TABLE1 set id_migration = id;

select * from MY_TABLE1;