PL / SQL更新触发器（入门）

Question

I have two tables. Table 1 includes a brief movie summary, Table 2 contains the entire movie bio.

I'd like to create an on update trigger that occurs when I update table 1. Essentially I want the first 30 characters to be updated in the table 1 movie summary, while the entire movie bio is updated in Table 2.

Any ideas to how I would begin this task?

Answer 1

It's been a while since I worked with PL/SQL but I would try something like this:

Create Or Replace Trigger update_movie_bio
Before Update On Table1
For Each Row

Begin
    UPDATE Table2
    SET movie_bio = :new.movie_bio
    WHERE movie_id = :new.movie_id
End;

So then you would update Table 1 with the first 30 characters and then this would automatically fire and update Table 2.

To update Table 1 the query would look like this:

UPDATE Table1
SET movie_summary = SUBSTR("movie_summary", 0, 30)
WHERE movie_id = movie_id