plsql - PL/SQL Update Trigger (Beginner) -

I have two tables Table 1 contains a short film summary, the table 2 contains the entire film bio.

I would like to make one on the updated trigger which happens when I update the table 1. Basically I want to update the first 30 characters in the Table 1 movie summary, while the whole movie is in Bio Updated Table 2.

Any ideas how will I start this work? It has been a while since working with PL / SQL, but I try to do something like this:

  Create or update the replacement _movie_bio Update 2 table for every row before updating table 2 Movie_bio =: new.movie_bio where movie_id =: new.movie_id end;  

Then you will update Table 1 with the first 30 characters and then it will automatically update the 2 more tabs.

  Update Table 1 SET movie_smurry = SUBSTR ("Movie_smurry", 0, 30) where movie_id = movie_id