I am working with room persistence library in android, i would appreciate if someone can help me in using foreign key, how to get data by using foreign key.
There is a nice tutorial that i used :
it alse give informations about :
When we use foreign key dont forget to put
onDelete = ForeignKey.CASCADE this way if you delete an data it will also delete de dependency. This way you won’t have false data or data that are never use
Just to summarize the above posts for future readers:
The foreign key syntax in Kotlin is
@Entity(foreignKeys = arrayOf(ForeignKey(entity = ParentClass::class, parentColumns = arrayOf("parentClassColumn"), childColumns = arrayOf("childClassColumn"), onDelete = ForeignKey.CASCADE)))
The foreign key syntax in Java is:
@Entity(foreignKeys = @ForeignKey(entity = ParentClass.class, parentColumns = "parentClassColumn", childColumns = "childClassColumn", onDelete = ForeignKey.CASCADE))
You can refer to the official documentation for more information.