Question

This is basically how my database looks like

ID | descendant | father | mother
---------------------------------
1       X            Y       Z
2       Y            A       B

Letters X,Y,Z,A,B represents some code or number

For example if I change code Y to R in line 1 (ID=1) I would like to change every field where I have code Y to code R or vice versa, if I change Y to R in line 2 so automatically would be change Y to R in line 1

The most important thing is if some code is changed to another, like I sad Y to R or to G whatever, every record in database that has code Y should be changed to R or G.

Could I do that with triggers. Or what other way could be used. (My users has ability to change record via my C# application)

Answer 1

Use triggers like this, one for each field:

CREATE TRIGGER update_descendant
AFTER UPDATE OF descendant ON MyTable
BEGIN
    UPDATE MyTable SET descendant = NEW.descendant WHERE descendant = OLD.descendant;
    UPDATE MyTable SET father     = NEW.descendant WHERE father     = OLD.descendant;
    UPDATE MyTable SET mother     = NEW.descendant WHERE mother     = OLD.descendant;
END;

(If the descendant column is unique, you don’t need to update it.)