两个主键，一个自动生成

Question

我想有两个主键，一个应该是自动生成的，我尝试这样做：

@Entity(tableName = "object_to_group", primaryKeys = {"id" , "object_id"},)
public class ObjectsToGroup {
@ColumnInfo(name = "id",autoGenerate = true)
public long id;

但是编译器显示错误

当我这样做时：

@PrimaryKey(autoGenerate = true)
@ColumnInfo(name = "id")
public long id;

编译器显示错误，我该怎么办？

Answer 1

复合主键无法添加自动增量。或者，您可以使用唯一索引。例如

@Entity(tableName = "object_to_group", indices = {@Index(value = 
{"object_id"}, unique = true)})
public class ObjectsToGroup {
@PrimaryKey(autoGenerate = true)
private int id;
@ColumnInfo(name = "object_id")
private int object_id;
}