android-ORMLite多对多关系

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;
}

我面临的问题是在创建表时使用ORMLite,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;
}

这似乎是一种奇怪的方式？

解决方法:

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法是使用“联接表”.在您的情况下,将有一个名为Test1Test2Join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;
}

有关更多信息,请参见many-to-many example.

标签：many-to-many,dao,ormlite,android
来源： https://codeday.me/bug/20191123/2064468.html