如何在一组行之后或有条件地在没有PL/SQL块的情况下增加oracle序列?

I am trying to perform code rewrite. One among them was this monster. I am having a set of normal DML's and all of a sudden I have this PL/SQL Block inside a script (see the current solution in place) which looks odd among SQL DML's.I am trying to perform code rewrite. One among