Raising Error not working in MySQL trigger

I am trying to raise an error within my trigger if a person's lastname is not in full caps or if the first letter of their firstname is not in caps . But my code doesn't seem to raise an alarm if those scenarios are met. Can someone please explain to me how I can do so ?

This is my table:

DROP TABLE IF EXISTS people;
CREATE TABLE IF NOT EXISTS people (
Id_People smallint(5) unsigned NOT NULL AUTO_INCREMENT,
Firstname varchar(20) NOT NULL,
Lastname varchar(20) NOT NULL,
Birth     DATE,
PRIMARY KEY (Id_People)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=1002 ;DROP TRIGGER IF EXISTS insert_people;

This is my trigger

DROP TRIGGER IF EXISTS insert_people;
DELIMITER $$
CREATE TRIGGER insert_people BEFORE INSERT ON people
FOR EACH ROW BEGIN 
    IF NOT  (NEW.Lastname like UCASE ) THEN 
          SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'the lastname must be in full caps ';
           
    ELSE IF
         NOT (NEW.Firstname like ucfirst ) THEN
           SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'the first letter of the firstname must be in caps'; 
    
     END IF; 
  END IF;
 
END$$

Solution

You code to find those is not correct.

Please add DELIMITER to the trigger code, as it isn't necessary in the example site

DROP TABLE IF EXISTS people;
CREATE TABLE IF NOT EXISTS people (
Id_People smallint(5) unsigned NOT NULL AUTO_INCREMENT,
Firstname varchar(20) NOT NULL,
Lastname varchar(20) NOT NULL,
Birth     DATE,
PRIMARY KEY (Id_People)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=1002 ;DROP TRIGGER IF EXISTS insert_people;

CREATE TRIGGER insert_people BEFORE INSERT ON people
FOR EACH ROW BEGIN 
    IF NOT  (NEW.Lastname=BINARY UPPER(NEW.Lastname)) THEN 
          SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'the lastname must be in full caps ';
           
    ELSE IF
         NOT (ASCII(NEW.Firstname) BETWEEN 65 AND 90 ) THEN
           SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'the first letter of the firstname must be in caps'; 
    
     END IF; 
  END IF;
 
END

INSERT INTO people VALUES (NULL,'Hallo','Kitty','1980-01-01')

the lastname must be in full caps

INSERT INTO people VALUES (NULL,'hallo','KITTY','1980-01-01')

the first letter of the firstname must be in caps

db<>fiddle here