Ebean ManyToMany查询 [英] Ebean ManyToMany query

问题描述

我有两个课程，用户和汽车。两者都有ManyToMany相互映射。

I have two classes, user and car. Both have ManyToMany mapping to each other.

用户：

@Entity
public class User extends Model {

    private int year;

    @ManyToMany(cascade=CascadeType.ALL)
    private List<Car> cars;
}

汽车：

@Entity
public class Car extends Model {
    @ManyToMany(mappedBy = "cars", cascade=CascadeType.ALL )
    private List<User> users;
}

使用ebean，我只想查询那些从1999年开始的汽车在列表中提供用户。我不想在Java代码中迭代用户的汽车列表。

Using ebean, I would like to query only those cars from year 1999 that have give user in their list. I do not want to iterate over the user's car list in Java code.

我没有找到任何文档，多少对多的查询应该是什么样子。所以我想这样：

I didn't find any documentation how many-to-many queries should look like. So I would something like this:

public List<Car> findCars(int year, User user) {
    return Car.find.where().eq("year", int).eq("users", user).findList();
}

这是否可以使用Ebean？

Is this possible with Ebean?

推荐答案

检查类似的提问（和回答）

最有可能你的取景器应该是这样的：

Most probably your finder should look like:

public List<Car> findCars(int year, User user) {
    return find.where().eq("year", year).eq("users.id", user.id).findList();
}

BTW我假设你有一些 id 字段，但只是没有告诉我们。同时公开您的字段，因此您不需要为每个字段编写getter / setter。

BTW I assume that you have some id field but just didn't show us. Also make your fields public, so you won't need to write getters/setters for each.

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