oracle11g - Bulk update of column values of entire table -

we have oracle 11g database table around 35 million rows. in situation have update values of 1 column. column indexed.

i have script can generate updated values , can populate in text file.

i'm looking strategy bulk update table. can afford downtime of around 10 hours.

will idea to

• dump entire table flat file
• update values using scripting language
• reload entire table
• rebuild indexes

what pitfalls 1 can encounter?

i'm not competent in pl/sql. there way solve in pl/sql or way "within" database itself?

thanks, prabhu

the fastest way create external table based on flat file of update values , then:

create table new_table   select o.col1, o.col2, o.col3, ..., x.value coln   old_table o   join extern_table x on ...; 

(make sure join returns rows old_table. join may need outer join.)

-- drop foreign key constraints reference old_table alter table child1 drop constraint fk_to_old_table1; ...  drop table old_table;  rename new_table old_table;  -- re-create indexes , constraints on old_table alter table old_table add constraint oldpk primary key (col1); ...  -- re-create dropped foreign key constraints old_table alter table child1 add constraint fk_to_old_table1 ...; ...