问题描述
我正在尝试在我的 Android 应用程序中实现 Room,但出现错误
I am attempting to implement Room in my Android application, but am getting the error
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
列被切换,但是我无法弄清楚如何更改 TableInfo.
I do see the uts
and mid
columns are switched, however I have not been able to figure out how to change the column order in the TableInfo
.
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,有人可以帮我订购列吗?
Can anyone help me with ordering the columns if that is the issue that I'm encountering?
推荐答案
我相信您的问题不在于顺序,而在于列名的大小写.
I believe that your issue is not the order but rather the case of the column names.
例如以下数据库(另存为资产 appcase.db)定义为:-
For example the following database (save as asset appcase.db) defined with :-
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:-
However, using a database who's DDL is:-
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,您需要像上面一样更改 DDL 或更改实体以反映 DDL,例如以下适用于原始(失败的)DDL:-
So you either need to change the DDL as above or change the Entity to reflect the DDL e.g. the following works with the original (failed) DDL:-
@Entity(tableName = "viewLog")
data class ViewLogModel(
@PrimaryKey val MID: Int,
val VID: Int,
val UTS: Float)
或者你可以使用 @ColumnInfo
之类的:-
or alternately you could use @ColumnInfo
's like:-
@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)
这篇关于预打包数据库的架构列顺序无效的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!