一对一关系 [英] Sequelize one to one relation

问题描述

我有两个模型，视频和帧.

I have two models, Video and Frame.

Frame.belongsTo(models.Video);
Video.hasMany(models.Frame, { as: "Frames" });

我现在需要一种方法来指定视频的第一帧和最后一帧，但无法正常工作.

I now need a way to specify first and last frame for a video, but can't get it to work.

我尝试过:

Video.hasOne(Frame, { as: "FirstFrame" });
Video.hasOne(Frame, { as: "LastFrame" });

但是在Frames表而不是Videos表中创建FirstFrameId和LastFrameId.我需要有可用的video.get/setFirstFrame()和video.get/setLastFrame()函数.我该怎么办?

but that creates FirstFrameId and LastFrameId in the Frames table instead of the Videos table. I need to have video.get/setFirstFrame() and video.get/setLastFrame() functions available. How can I do this?

推荐答案

您不需要像最初显示的那样设置belongeTo和hasMany.只能使用一种，具体取决于您的数据库架构.

You don't need to set belongTo and hasMany as you show at first. Use only one depending on your db schema.

要在视频模型上获取FirstFrameId和LastFrameId，您需要使用:

For get FirstFrameId and LastFrameId on the Videos Model you need to use:

Video.belongsTo(Frame, {as: 'FirstFrame'});
Video.belongsTo(Frame, {as: 'LastFrame'});

这是在Sequelize文档上指定的，您可以在此处进行检查>

This is specify on the Sequelize docs and you can check it here

即使它被称为HasOne关联，对于大多数1:1关系 您通常需要BelongsTo关联，因为BelongsTo将添加 源上的foreignKey，hasOne将添加到目标上."

"Even though it is called a HasOne association, for most 1:1 relations you usually want the BelongsTo association since BelongsTo will add the foreignKey on the source where hasOne will add on the target."

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