To add a new column of date type in all the tables to be partitioned, then update the column value periodically based on some id's and other joins from other tables.
create new tablespaces to for each partition table or single partition and then partition the table ,Problem here is updating
for 10 tables each holding around 30-40 million rows(5 tables) and remaing 5 holding 10-15 million rows how long update will go and what should be the approch we are not able to finalize.

create new_table table as select * from old_table
partition new_table.
drop old_table;
rename new_table to Old_Table;
create constaint,indexes on new_table;

Now here if i want to create constraint and Index on new_Table i can't create with same name since all those names already exists for OLD_TABLE, so if dropped OLD_TABLE then constraints and indexes get dropped, and moreover if this OLD_TABLE is referencing or this is Master table then dropping problem,
or even if we dropped then how to recreate the constraints,referential integrity, indexes of same name as it was for old table..