Question

我正在运行一个新项目，其中有两个表groups和members。它们当时都是空的，并且成员表group_id有一个预备键约束。

现在我开始创建一个可能稍后有很多成员的组，但是，当我尝试创建它时，我收到以下消息：

SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`cogro`.`groups`, CONSTRAINT `groups_ibfk_1` FOREIGN KEY (`id`) REFERENCES `members` (`group_id`) ON DELETE NO ACTION ON UPDATE NO ACTION)

非常感谢任何帮助或指导。

Answer 1

您输入了错误的外键方向。目前members.group_id引用groups（为了在id = 1中添加members条目，您应该在group_id = 1中添加CONSTRAINT `members_group_id_fk` FOREIGN KEY (`group_id`) REFERENCES `groups` (`id`)的条目<） / p>

将定义更改为：

var myElement = document.getElementById('myCanvas');

var mc = new Hammer(myElement,
{
    hold: false,
    release: false
});

mc.add(new Hammer.Press({
    event: 'press',
    pointer: 1,
    threshold: 30,
    time: 1
}));
mc.on("press", function(event)
{
    //This works, but only single touch, until touch is lifted
    //can I do second.
    x1 = event.center.x;
    y1 = event.center.y;

    //This doesn't -> Trying new things
    x2 = event.touches[1].x;
    y2 = event.touches[1].y;        
});

外键约束在空表中失败

1 个答案: