Question

Convert DataType from Number to Varchar2 in a table with huge data

Asked by: rajesh_agr

I have a table in which I need to convert data type of one column from Number to Varchar2. There are huge # of records in this table but all are having integer value.
Pl. advise how to convert it.
Thanks.

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Asked On
2009-01-29 at 14:03:33ID24096548
Topic

Oracle Database

Participating Experts
3
Points
125
Comments
4

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Answers

 

by: ravindran_eeePosted on 2009-01-29 at 15:29:44ID: 23503937

Oracle does not allow this conversion.. So follow the steps..

   1. Add new column (temp) with desired datatype.
   2. Copy data to the new column
   3. Drop the original column
   4. Add new column with the name of the original and the desired datatype
   5. Copy data to the new column from the temp column
   6. Drop temp column

 

by: dzamfirPosted on 2009-01-29 at 18:19:19ID: 23504711

Hey ravindran_eee, you cannot say that Oracle doesn't allow this conversion, because is not true.

You can do as in the example below :

ALTER TABLE my_table ( my_column varchar2(10) );

But is not recommended to play with this if you have some values on that column. Recommended is to export the rows, alter the table and then re-import the data.

So that's the truth about that... not that the Oracle does not allow...



Or, the solution provided by you.  ( Personally I will go for your solution, rather to export/re-import the data on that table)

 

by: sventhanPosted on 2009-01-30 at 07:15:10ID: 23509009

20120131-EE-VQP-002

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