Question

我有这个触发器：

CREATE OR REPLACE TRIGGER TR_SIGHTING_DESC
BEFORE INSERT ON sightings
FOR EACH ROW
BEGIN
SELECT bird_name
INTO bn
from birds
where bird_id = :new.bird_id;    
    :new.description := 'A bird of the species ' 
                        || bn 
                        || ' was spotted in the ' 
                        || :new.latitude || ','|| :new.longitude 
                        || ' part of the observation area';
END;
/

它一直说它无效。我试图检索bird_name形成其相应的ID，例如，这被插入到目击表中：

INSERT INTO sightings (spotter_id, bird_id, latitude,
longitude, sighting_date)
VALUES (2457, 901, -28.0, 152, '09-MAR-2016');

Answer 1

你必须声明变量

CREATE OR REPLACE TRIGGER TR_SIGHTING_DESC
BEFORE INSERT ON sightings
FOR EACH ROW
DECLARE bn birds.bird_name%type;
BEGIN
SELECT bird_name
INTO bn
from birds
where bird_id = :new.bird_id;    
    :new.description := 'A bird of the species ' 
                        || bn 
                        || ' was spotted in the ' 
                        || :new.latitude || ','|| :new.longitude 
                        || ' part of the observation area';
END;
/

Answer 2

好醇2200 你必须在插入之前声明dn。

选择进入触发器语句

2 个答案: