Room Upsert成功更新却返回-1的问题排查求助

问题描述 #

我之前了解到Room的Upsert操作出错时通常返回-1，但最近在项目中发现，即使更新操作成功执行（通过App Inspection确认数据库条目已被修改，比如性别从female改为male），Upsert仍然返回-1，导致错误提示被触发。当前项目使用Room版本为2.6.1，想知道哪里出现了认知偏差？

相关代码 #

Room配置 #

@Entity(tableName = "birth_defect_beneficiary_details")
data class BirthDefectBabyDetails(
    @PrimaryKey(autoGenerate = true)
    val id: Int? = null,

    val dateOfBirth: Long,
    val sex: String,

    val motherName: String,
    val fatherName: String,

    val address: String,
    val contactNumber: String,

    val condition: String,

    val patientContacted: Boolean
)

@Dao
interface BDBabyDetailsDao {

    @Query("SELECT * FROM birth_defect_beneficiary_details ORDER BY dateOfBirth DESC")
    fun getDetailsOfAllBabies(): Flow<List<BirthDefectBabyDetails>>

    @Upsert
    suspend fun upsertEntry(entry: BirthDefectBabyDetails): Long

    @Delete
    suspend fun deleteEntry(entry: BirthDefectBabyDetails): Int

    @Query("DELETE FROM birth_defect_beneficiary_details")
    suspend fun deleteAllEntries()
}

@Database(
    entities = [BirthDefectBabyDetails::class],
    version = 1,
    exportSchema = false
)
abstract class BDBabiesDatabase : RoomDatabase() {
    abstract val babyDao: BDBabyDetailsDao
}

interface BabyDetailsEntryRepository {
    fun getAllBabiesStream(): Flow<List<BirthDefectBabyDetails>>
    suspend fun upsertEntry(entry: BirthDefectBabyDetails): Long
    suspend fun deleteEntry(entry: BirthDefectBabyDetails): Int
    suspend fun deleteAllEntries()
}

class BDBabyDetailsLocalRepository @Inject constructor(
    private val babyDao: BDBabyDetailsDao
) : BabyDetailsEntryRepository {
    override fun getAllBabiesStream(): Flow<List<BirthDefectBabyDetails>> {
        return babyDao.getDetailsOfAllBabies()
    }

    override suspend fun upsertEntry(entry: BirthDefectBabyDetails): Long {
        return babyDao.upsertEntry(entry = entry)
    }

    override suspend fun deleteEntry(entry: BirthDefectBabyDetails): Int {
        return babyDao.deleteEntry(entry = entry)
    }

    override suspend fun deleteAllEntries() {
        babyDao.deleteAllEntries()
    }
}

ViewModel中执行Upsert的代码 #

private fun upsertEntry() {

    // some codes...

    viewModelScope.launch(IO) {
        try {
            val result = babyRepository.upsertEntry(newEntry)
            Log.d("DPDC", "$result")
            if (result != -1L) {
                triggerEvent(VMEvents.EntryAdded("B/O ${newEntry.motherName}"))
            } else {
                triggerEvent(VMEvents.ShowError("Failed to add/update entry"))
            }
        } catch (e: Exception) {
            triggerEvent(VMEvents.ShowError("Error occurred: ${e.message}"))
        }
    }

    // some more codes...
}

newEntry声明为val newEntry: BirthDefectBabyDetails

问题原因与解决方案 #

核心原因 #

你对Room @Upsert的返回值逻辑理解有误：

• 当执行插入操作时，Room返回新插入条目的自增主键ID
• 当执行更新操作时，如果实体使用autoGenerate = true的自增主键，Room固定返回**-1**，这是正常设计，并非操作失败

Room的Upsert操作只有在真正发生异常（比如约束冲突、数据库连接错误）时才会抛出Exception，返回-1仅仅代表本次是更新动作，而非插入。

解决方案 #

修改ViewModel中的判断逻辑，去掉基于返回值的错误判断，只要没有抛出异常就判定操作成功：

private fun upsertEntry() {
    // some codes...
    viewModelScope.launch(IO) {
        try {
            babyRepository.upsertEntry(newEntry)
            triggerEvent(VMEvents.EntryAdded("B/O ${newEntry.motherName}"))
        } catch (e: Exception) {
            triggerEvent(VMEvents.ShowError("Error occurred: ${e.message}"))
        }
    }
    // some more codes...
}

额外说明 #

如果需要区分插入和更新动作，可以通过实体的主键是否为null来判断：

• 若newEntry.id == null，执行的是插入操作，返回新生成的ID
• 若newEntry.id != null，执行的是更新操作，返回-1

这是Room 2.5及以上版本针对自增主键的@Upsert注解的标准行为。

内容的提问来源于stack exchange，提问作者TheSelfTaughtNoob