Question

第一次安装我的应用程序时，我以编程方式创建数据库。到目前为止工作正常。但是当我想添加一个触发器时，我得到一个异常，说IF＆＃34;附近有＃34;语法错误。问题是，我无法跨越源代码中的多行。那么我该怎么做呢？

private void createTriggers(SQLiteDatabase database) {

    final String triggerLocationArchived = "CREATE TRIGGER location_archived AFTER UPDATE ON location FOR EACH ROW BEGIN IF NEW.deleted <> OLD.deleted THEN UPDATE sector set sector.deleted = NEW.deleted WHERE sector.location = NEW._id; END IF; END;";

    database.execSQL(triggerLocationArchived);
}

有两个表：位置和扇区。每个都有一个INTEGER标志，指示该行是否已存档。因此，如果父项（位置）已存档，我希望所有子项（一个位置内的扇区）都可以存档。

Answer 1

尝试此命令：

 CREATE TRIGGER location_archived 
 AFTER UPDATE ON location 
 FOR EACH ROW 
 WHEN NEW.deleted <> OLD.deleted 
 BEGIN 
    UPDATE sector 
    set deleted = NEW.deleted 
    WHERE location = NEW._id; 
 END

您的代码如下所示：

private void createTriggers(SQLiteDatabase database) {

     final String triggerLocationArchived = "CREATE TRIGGER location_archived AFTER UPDATE ON [location] FOR EACH ROW WHEN NEW.deleted <> OLD.deleted BEGIN UPDATE sector set deleted = NEW.deleted WHERE location = NEW._id; END";

     database.execSQL(triggerLocationArchived);
}

Sqlite：以编程方式创建触发器

1 个答案: