DROP or MODIFY COLUMN on Oracle 8 system

Hi

I need to change the datatype of a column from VARCHAR2 to FLOAT preserving all data, which actually represent numeric data. I have to do it on an oracle8 enterprise system. Afaik

        ALTER TABLE tablename DROP COLUMN column and / or

        ALTER TABLE tablename MODIFY (column <NEW_DATATYPE>) doesn't work here, is that correct?

So my migration plan is as follows:

1. create a temporary table with same schema as the src-table (except for the changed datatype of the one column)
2. insert / copy all old data into the new table problem: how will i keep values of auto-incremental fields?
3. Drop old table problem: how can i drop it, when its PK has references?
4. Re-create old table, with correct datatype for the one column
5. insert / copy data from tmp-table. problem: same as in 2.
6. drop temp-table

Can anybody please help me on how to solve the problems mentioned. Or is there a better strategy (maybe built-in management tools?)

Thanks,
Alex Received on Fri May 12 2006 - 05:24:31 CDT