android - ORMLite 多对多关系

Question

为了用 ORMLite 在这两个类之间建立多对多关系:

@DatabaseTable(tableName = "test1")
public class Test1 {
    @ForeignCollectionField
    private ForeignCollection<Test2> test2Collection;
}

@DatabaseTable(tableName = "test2")
public class Test2 {
    @ForeignCollectionField
    private ForeignCollection<Test1> test1Collection;
}

我面临的问题是 ORMLite 在创建表时不知道此类之间的外键..

为了建立这种关系，我必须像这样在每个类上添加一个 ForeignDatabaseField:

@DatabaseTable(tableName = "test1")
public class Test1 {
    @DatabaseField(foreign = true, foreignAutoRefresh = true)
    private Test2 test2;
    @ForeignCollectionField
    private ForeignCollection<Test2> test2Collection;
}
@DatabaseTable(tableName = "test2")
public class Test2 {
    @DatabaseField(foreign = true, foreignAutoRefresh = true)
    private Test1 test1;
    @ForeignCollectionField
    private ForeignCollection<Test1> test2Collection;
}

好像是个奇怪的方法？

Answer 1

In order to make this relation do I have to add a single ForeignDatabaseField on each class like that:

对于多对多关系，将对象关联在一起的最佳方式是使用“连接表”。在您的情况下，会有一个名为 Test1Test2Join 或其他名称的第三个表。

@DatabaseTable(tableName = "test1test2join")
public class Test1Test2Join {
    @DatabaseField(generatedId = true)
    private long id;
    @DatabaseField(foreign = true)
    private Test1 test1;
    @DatabaseField(foreign = true)
    private Test test2;
}

有关详细信息，请参阅 many-to-many example .