Truncate table in Oracle getting errors

Question

I got the problem is when I run following command in Oracle, I encounter the error.

Truncate table mytable;

Errors:

Answer 1

A typical approach to delete many rows with many constraints is as follows:

• create mytable_new with all the columns but without constrains (or create constraints disabled);
• copy whatever data you need from mytable to mytable_new.
• enable constraints on mytable_new to see that everything is ok.
• alter any constraints that reference mytable to reference mytable_new instead and see that everything is ok.
• drop table mytable.
• alter table mytable_new rename to mytable.

It's far faster than deleting a million records with many slow constraints.