我正在使用Room，并且发现了将主键设置为自动生成的问题，
@PrimaryKey(AutoGenerate=True)
如果我执行一个INSERT操作，然后执行一个UPDATE操作，则为这些操作生成的键不同，因此，我的数据不会更新。

@Entity(tableName = "test_table")
public class TestEntity {

    @PrimaryKey(autoGenerate = true)
    private int uid;

    @ColumnInfo(name = "expiration_date_access_token")
    private String expirationDateAccessToken;

    /**
     * Getter for retrieving primary key
     *
     * @return Primary key
     */
    public int getUid() {
        return uid;
    }

    /**
     * Setter for setting primary key
     *
     * @param uid Primary key
     */
    public void setUid(int uid) {
        this.uid = uid;
    }

    /**
     * Getter for retrieving expiration date of access token
     *
     * @return Expiration date of access token
     */
    public String getExpirationDateAccessToken() {
        return expirationDateAccessToken;
    }

    /**
     * Setter for setting expiration date of access token
     *
     * @param expirationDateAccessToken Expiration date of access token
     */
    public void setExpirationDateAccessToken(String expirationDateAccessToken) {
        this.expirationDateAccessToken = expirationDateAccessToken;
    }
}

下面是一个DAO示例

@Dao
public interface TestDao {

    @Query("SELECT * FROM test_table")
    List<TestEntity> getAll();

    @Query("DELETE FROM test_table")
    void deleteAll();

    @Insert
    void insert(TestEntity testEntity);

    @Delete
    void delete(TestEntity testEntity);

    @Update
    void update(TestEntity testEntity);
}

这是我的AppDatabase

@Database(entities = {TestEntity.class}, version = 1, exportSchema = false)
public abstract class AppDatabase extends RoomDatabase {

    private static final String DATABASE_NAME = "room.test.db";
    private static AppDatabase APP_DATABASE_INSTANCE;

    public abstract TestDao testDao();

    public static AppDatabase getAppdatabase(@NonNull Context context) {
        if (FrameworkUtils.checkIfNull(APP_DATABASE_INSTANCE)) {
            APP_DATABASE_INSTANCE = Room.databaseBuilder(context.getApplicationContext(),
                    AppDatabase.class, DATABASE_NAME).build();
        }
        return APP_DATABASE_INSTANCE;
    }

    /**
     * Method is used to destroy database instance
     */
    public static void destroy() {
        APP_DATABASE_INSTANCE = null;
    }
}

我已经将我的LiveData连接到我的存储库，然而，出于下面的简单原因，我也执行了相同的操作。

Thread t = new Thread(new Runnable() {
            @Override
            public void run() {
                // update database tables
               TestEntity testEntity = new TestEntity();
               // if I uncomment setting uid, which is the hardcoded primary key
               // value, the update will happen. If I do not include this, and 
               // just try to update my data, a new primary key is generated and
               // the old data does not get updated.

               // testEntity.setUid(1); 
               testEntity.setExpirationDateAccessToken("12345");
               AppDatabase.getAppdatabase(context).testDao().update(testEntity);

            }
        });

我的问题是，使用@PrimaryKey(AutoGenerate=真)的模式是什么？通过对主键执行以下硬编码，我可以让一切完美地工作，但我认为这不是必需的。
编辑

@PrimaryKey(autoGenerate = true)
    private int uid = 1; <---- works with any hardcoded int value