SORM:如何声明外键? [英] SORM: How can I declare foreign keys?

问题描述

我对SORM非常感兴趣，但是当我尝试使用它时，就会遇到问题.假设我有两个实体:

I'm very interested in SORM, but when I try to use it I bump into problem. Suppose I have two entities:

case class User(login: String, firstName: String, lastName: String)
case class UserSite(userId: Int, name: String, url: String)

如何声明外键关系UserSite.userId-> User.id?我看到了ForeignKey类，但是没有任何使用它的示例.

How can I declare foreign key relation UserSite.userId -> User.id? I see class ForeignKey, but there are no any example of using it.

谢谢.

推荐答案

一个很好的机会来展示SORM的功能.

A very nice opportunity to exhibit the powers of SORM.

如SORM的功能所述，它从 ALL 中抽象出来>关系概念.这包括外键.

As indicated in the Features of SORM, it abstracts away from ALL relational concepts. This includes foreign keys.

外键抽象是通过自然直接引用提供的，这些直接引用是要使用外键引用的这些实体.因此，您应该使用user属性指向User本身，而不是userId指向User的id:

The foreign key abstraction is provided by natural direct references to these entities you wanted to refer to with a foreign key. So instead of userId pointing to the id of User, you should point to the User itself with the user property:

case class User(login: String, firstName: String, lastName: String)
case class UserSite(user: User, name: String, url: String)

在引擎盖下，这将完全转换为您希望通过外键实现的目标.但问题是您不必在意.

Under the hood this will translate exactly into what you wanted to achieve with the Foreign Key. But the thing is you don't have to care about it.

旁注.在使用SORM时，您应该毫无限制地按照希望在Scala中使用模型的方式来设计模型，并且绝对应该把设计模型时习惯的所有关系概念都抛在脑后.这就是SORM的方式.

关于文档和库结构.该方法非常简单:如果没有记录，则不应将其用作公共API的一部分.同样，对于SORM的当前(v.0.3.x)结构，公共API的所有组件都位于sorm._程序包中，因此另一个规则是，如果不存在，则不打算将其用于公共API.

Concerning the documentation and library structure. The approach is very simple: if it's not documented, it is not intended to be used as part of public API. Also with the current (v. 0.3.x) structure of SORM all components of the public API reside in the sorm._ package, so another rule is if it's not there it is not intended for public API.

这篇关于SORM:如何声明外键?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！