预打包的数据库具有无效的架构列顺序

Question

我正在尝试在我的 Android 应用程序中实现 Room，但出现错误

java.lang.IllegalStateException: Pre-packaged database has an invalid schema: viewLog(myApp.ViewLogModel).
 
Expected:
TableInfo{name='viewLog', columns={vid=Column{name='vid', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, mid=Column{name='mid', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}, uts=Column{name='uts', type='REAL', affinity='4', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[]}
 
Found:
TableInfo{name='viewLog', columns={VID=Column{name='VID', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, UTS=Column{name='UTS', type='REAL', affinity='4', notNull=true, primaryKeyPosition=0, defaultValue='null'}, MID=Column{name='MID', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}}, foreignKeys=[], indices=[]}

我确实看到uts 和mid 列已切换，但是我无法弄清楚如何更改TableInfo 中的列顺序。

我的房间数据库代码是

@Database(entities = [ViewLogModel::class, CacheInputModel::class, CachePageModel::class], version = 1)
    abstract class MyDatabase : RoomDatabase() {
    abstract fun cacheInputDao(): CacheInputDao
    abstract fun cachePageDao(): CachePageDao
    abstract fun viewLogDao(): ViewLogDao

    companion object {
        // For Singleton Instance
        @Volatile
        private var INSTANCE: MyDatabase? = null

        fun getAppDataBase(context: Context): MyDatabase {
            return INSTANCE ?: synchronized(this) {
                INSTANCE ?: Room.databaseBuilder(context.applicationContext, MyDatabase::class.java, "appDatabase")
                    .createFromAsset("app.db")
                    .build()
            }
        }

        fun destroyDataBase(){
            INSTANCE = null
        }
    }
}

ViewLogModel 是

@Entity(tableName = "viewLog")
data class ViewLogModel(
    @PrimaryKey val mid: Int,
    val vid: Int,
    val uts: Float)

ViewLogDao 是

@Dao
interface ViewLogDao {
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insertOrUpdateViewLog(viewLog: ViewLogModel)

    @Update
    suspend fun updateViewLog(viewLog: ViewLogModel)

    @Delete
    suspend fun deleteAllViewLog(viewLog: ViewLogModel)

    @Query("DELETE FROM viewlog WHERE VID= :vid OR UTS < :uts")
    suspend fun deleteViewLog(vid: Int, uts: Float)

    @Query("SELECT * FROM viewLog")
    suspend fun getAll(): List<ViewLogModel>

    @Query("SELECT * FROM viewLog WHERE vid = :vid")
    suspend fun getViewLog(vid: Int): List<ViewLogModel>
}

如果这是我遇到的问题，谁能帮我对列进行排序？

Answer 1

我相信您的问题不在于顺序，而在于列名的大小写。

例如以下数据库（另存为资产 appcase.db）定义为：-

CREATE TABLE "viewLog" (
  "MID" INTEGER NOT NULL,
  "UTS" real NOT NULL,
  "VID" INTEGER NOT NULL,
  PRIMARY KEY ("MID")
);

失败：-

 Caused by: java.lang.IllegalStateException: Pre-packaged database has an invalid schema: viewLog(a.a.so67711264kotlinroomprepackageddb.ViewLogModel).
 Expected:
TableInfo{name='viewLog', columns={vid=Column{name='vid', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, mid=Column{name='mid', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}, uts=Column{name='uts', type='REAL', affinity='4', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[]}
 Found:
TableInfo{name='viewLog', columns={VID=Column{name='VID', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, UTS=Column{name='UTS', type='real', affinity='4', notNull=true, primaryKeyPosition=0, defaultValue='null'}, MID=Column{name='MID', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}}, foreignKeys=[], indices=[]}

但是，使用 DDL 的数据库是：-

CREATE TABLE "viewLog" (
  "mid" INTEGER NOT NULL,
  "uts" real NOT NULL,
  "vid" INTEGER NOT NULL,
  PRIMARY KEY ("mid")
)

按预期工作。

因此，您要么需要更改上述 DDL，要么更改实体以反映 DDL，例如以下适用于原始（失败的）DDL：-

@Entity(tableName = "viewLog")
data class ViewLogModel(
    @PrimaryKey val MID: Int,
    val VID: Int,
    val UTS: Float)

或者您也可以使用@ColumnInfo 之类的：-

@Entity(tableName = "viewLog")
data class ViewLogModel(
    @PrimaryKey @ColumnInfo(name = "MID") val mid: Int,
    @ColumnInfo(name ="VID") val vid: Int,
    @ColumnInfo(name = "UTS") val uts: Float)