Question

如果在触发器上声明的当前表得到更新，我需要更新另一个表上的字段。但我需要在2个条件之后更新

    public class Match{
        public int participant1;
        public int participant2;
        public int winner;
        public boolean finalMatch;
        public int standingId;
    }

        public class Standings{
            public int id;
            public int firstPlace;
            public int SecondPlace;
        }

private static final String CREATE_TRIGGER_MATCH_UPDATE_BRACKET_WINNERS_F1 = "CREATE TRIGGER if not exists updatefields
        AFTER UPDATE OF  winner
            ON Match
            WHEN new.finalMatch = 1 AND new.winner = new.participant1
            BEGIN
            UPDATE Standings
                SET firstPlace = new.winner
                    SecondPlace = new.participant2
            WHERE id = new.standingId
        END;"

但这会引发错误。显然，只有＆＃34; WHEN条件＆＃34; for android上的触发器。现在我不确定如何检查它。正如我想在一个触发器上更新这两个字段。如果我做两个触发器，1用于设置＆＃34; firstPlace＆＃34;另一个用于＆＃34; secondPlace＆＃34;，第二个将在Standings表上，我不确定如何访问＃34; secondPlace＆＃34;值。

Answer 1

修复语法（trigger，update）错误后，接受触发器：

CREATE TRIGGER if not exists updatefields
AFTER UPDATE OF winner ON Match
WHEN new.finalMatch = 1 AND new.winner = new.participant1
BEGIN
    UPDATE Standings
    SET firstPlace  = new.winner,          -- comma here
        SecondPlace = new.participant2
    WHERE id = new.standingId;             -- semicolon here
END;

SQLITE触发器的多个条件

1 个答案: