我有一個包含資料的房間資料庫,現在我想向其中添加另一列。
Room 2.4.0-alpha01 及更高版本應該使自動遷移更容易,所以我這樣使用它:
...
version = 2,
autoMigrations = {
@AutoMigration(from = 1, to = 2)
},
exportSchema = true
然后在我的模型類中,我添加了新的列名并生成了它的 setter 和 getter,就像其他的一樣。
房間檔案說,如果房間由于復雜的模式更改而無法執行遷移,則會引發編譯時錯誤。但是,在我的情況下,我收到一個關于預期模式和新模式(我添加一列的模式)之間差異的運行時錯誤。
下面是錯誤:
java.lang.RuntimeException: Exception while computing database live data.
at androidx.room.RoomTrackingLiveData$1.run(RoomTrackingLiveData.java:92)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:919)
Caused by: java.lang.IllegalStateException: Migration didn't properly handle: accounts(com.bisform.susu.models.Account).
Expected:
TableInfo{name='accounts', columns={accountSavings=Column{name='accountSavings', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountName=Column{name='accountName', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountCreateTime=Column{name='accountCreateTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, numberOfDeposits=Column{name='numberOfDeposits', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, accountNumber=Column{name='accountNumber', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, numberOfWithdrawals=Column{name='numberOfWithdrawals', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, accountPayoutDate=Column{name='accountPayoutDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, phoneOfNextOfKin=Column{name='phoneOfNextOfKin', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountImageURI=Column{name='accountImageURI', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountID=Column{name='accountID', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=1, defaultValue='null'}, lastUpdatedDate=Column{name='lastUpdatedDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, phoneNumber=Column{name='phoneNumber', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountPayoutTime=Column{name='accountPayoutTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, lastUpdatedTime=Column{name='lastUpdatedTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, nameOfNextOfKin=Column{name='nameOfNextOfKin', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountCreateDate=Column{name='accountCreateDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, isPaidOut=Column{name='isPaidOut', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[]}
Found:
E/AndroidRuntime: TableInfo{name='accounts', columns={accountSavings=Column{name='accountSavings', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountName=Column{name='accountName', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountCreateTime=Column{name='accountCreateTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, numberOfDeposits=Column{name='numberOfDeposits', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, accountNumber=Column{name='accountNumber', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, numberOfWithdrawals=Column{name='numberOfWithdrawals', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, accountPayoutDate=Column{name='accountPayoutDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountImageURI=Column{name='accountImageURI', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountID=Column{name='accountID', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=1, defaultValue='null'}, lastUpdatedDate=Column{name='lastUpdatedDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, phoneNumber=Column{name='phoneNumber', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountPayoutTime=Column{name='accountPayoutTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, lastUpdatedTime=Column{name='lastUpdatedTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountCreateDate=Column{name='accountCreateDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, isPaidOut=Column{name='isPaidOut', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[]}
at androidx.room.RoomOpenHelper.onUpgrade(RoomOpenHelper.java:103)
...
請問我應該怎么做來處理這個錯誤?如何使用當前存在的自動遷移功能獲得正確遷移的空間?
uj5u.com熱心網友回復:
請問我應該怎么做來處理這個錯誤?如何使用當前存在的自動遷移功能獲得正確遷移的空間?
我相信只有在您以某種方式省略自動遷移時才會得到這個。我相信,使用您展示的代碼,唯一的方法是包含手動遷移,因為這將覆寫自動遷移。
如下所示的測驗顯示了這一點。
測驗
此測驗顯示了覆寫從 V1 到 V2 的 AutoMigration 的效果,以及未覆寫時遷移的作業方式。
該測驗基于根據您的預期 (v2) 和發現 (v1) 訊息構建的Accounts類。
所以 Accounts 類是:-
@Entity(tableName = "accounts")
class Accounts {
//String phoneOfNextOfKin; //<<<<< For V2 else commented out
//String nameOfNextOfKin; //<<<<< for V2 else commented out
String accountSavings;
String accountName;
String accountCreateTime;
Integer numberOfDeposits;
String accountNumber;
int numberOfWithdrawals;
String accountPayoutDate;
String accountImageURI;
@PrimaryKey
Long accountId;
String lastUpdatedDate;
String phoneNumber;
String accountPayoutTime;
String lastUpdatedTime;
String accountCreateDate;
boolean isPaidOut;
}
- 請注意帶有注釋 //<<<<< .... 的行是已更改的行(已為 V1 注釋掉并已包含在 V2 中)
- 即為 V2 添加了 2 列 phoneOfNextOfKin 和 nameOfNextOfKin
一個在版本之間不會改變的@Dao 類:-
@Dao
abstract class AccountsDao {
@Insert
abstract long insert(Accounts accounts);
@Query("SELECT * FROM accounts")
abstract List<Accounts> getAllFromAccounts();
}
@Database 類:-
@Database(
entities = {Accounts.class},
version = TheDatabase.DBVERSION
/* following line, if no schema saved, needs to be commented out */
, autoMigrations = {@AutoMigration(from = 1, to = 2)}
)
abstract class TheDatabase extends RoomDatabase {
abstract AccountsDao getAccountsDao();
public static final int DBVERSION = 1; //<<<<< change accordingly
private static volatile TheDatabase instance = null;
static TheDatabase getInstance(Context context) {
if (instance == null) {
instance = Room.databaseBuilder(
context,
TheDatabase.class,
"accounts.db"
)
.allowMainThreadQueries() //run on main thread for brevity and convenience
.addMigrations(MIGRATION_1_2) //<<<<< if included then Migration didn't properly handle:
.build();
}
return instance;
}
/* Only needed for creating error shown in question */
/* doesn't hurt if no addMigrations or when creating V1 */
static final Migration MIGRATION_1_2 = new Migration(1,2) {
@Override
public void migrate(@NonNull SupportSQLiteDatabase database) {
}
};
}
最后是以下活動:-
public class MainActivity extends AppCompatActivity {
TheDatabase db;
AccountsDao dao;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = TheDatabase.getInstance(this);
dao = db.getAccountsDao();
Accounts a = new Accounts();
a.accountCreateDate = "2021-01-01";
a.accountCreateTime = "08:00:00";
a.accountImageURI = "imageURI";
a.accountName = "MyAccount";
a.accountNumber = "0000000000";
a.accountPayoutDate = "2021-05-05";
a.accountPayoutTime = "10:00:00";
a.accountSavings = "savings";
a.lastUpdatedDate = "2021-05-03";
a.lastUpdatedTime = "09:15:00";
a.numberOfDeposits = 10;
a.numberOfWithdrawals = 5;
a.isPaidOut = false;
//a.nameOfNextOfKin = "Mr Next of Kin"; //<<<<< For V2
//a.phoneOfNextOfKin = "1111111111"; //<<<<< For V2
dao.insert(a);
for(Accounts account: dao.getAllFromAccounts()) {
String msg = "Account is " account.accountName " ID is " account.accountId;
if (TheDatabase.DBVERSION > 1) {
//msg = msg " next of kin is " account.nameOfNextOfKin; //<<<<< For V2
}
Log.d("ACCOUNTINFO", msg);
}
}
}
運行和結果:-
- 使用上述代碼(不包括 V2 代碼)并且未安裝應用程式。即創建 V1 資料庫:-
應用程式成功運行,資料庫檢查器顯示:-

架構與單行一樣符合預期。
- 不做任何更改再次運行
- 應用程式成功運行,資料庫檢查器顯示:-

3. 對 V2 的改動主要有:-
在包括近親的帳戶姓名和電話中。
in TheDatabase DBVERSION changed from 1 to 2 and .addMigrations left included
in the invoking activity the name and next of kin values are assigned values rather being commented out. the msg variable is concatenated to include the next of kin.
The App crashes with
:-
Caused by: java.lang.IllegalStateException: Migration didn't properly handle: accounts(a.a.so69442030javaroomautomigrationsaddcolumns.Accounts).
Expected:
2021-10-05 14:31:50.669 30268-30268/a.a.so69442030javaroomautomigrationsaddcolumns E/AndroidRuntime: TableInfo{name='accounts', columns={accountSavings=Column{name='accountSavings', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountName=Column{name='accountName', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountCreateTime=Column{name='accountCreateTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, numberOfDeposits=Column{name='numberOfDeposits', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountNumber=Column{name='accountNumber', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, numberOfWithdrawals=Column{name='numberOfWithdrawals', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, phoneOfNextOfKin=Column{name='phoneOfNextOfKin', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountPayoutDate=Column{name='accountPayoutDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountImageURI=Column{name='accountImageURI', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountId=Column{name='accountId', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=1, defaultValue='null'}, lastUpdatedDate=Column{name='lastUpdatedDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, phoneNumber=Column{name='phoneNumber', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountPayoutTime=Column{name='accountPayoutTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, nameOfNextOfKin=Column{name='nameOfNextOfKin', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, lastUpdatedTime=Column{name='lastUpdatedTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountCreateDate=Column{name='accountCreateDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, isPaidOut=Column{name='isPaidOut', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[]}
Found:
2021-10-05 14:31:50.670 30268-30268/a.a.so69442030javaroomautomigrationsaddcolumns E/AndroidRuntime: TableInfo{name='accounts', columns={accountSavings=Column{name='accountSavings', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountName=Column{name='accountName', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountCreateTime=Column{name='accountCreateTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, numberOfDeposits=Column{name='numberOfDeposits', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountNumber=Column{name='accountNumber', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, numberOfWithdrawals=Column{name='numberOfWithdrawals', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, accountPayoutDate=Column{name='accountPayoutDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountImageURI=Column{name='accountImageURI', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountId=Column{name='accountId', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=1, defaultValue='null'}, lastUpdatedDate=Column{name='lastUpdatedDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, phoneNumber=Column{name='phoneNumber', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountPayoutTime=Column{name='accountPayoutTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, lastUpdatedTime=Column{name='lastUpdatedTime', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, accountCreateDate=Column{name='accountCreateDate', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, isPaidOut=Column{name='isPaidOut', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[]}
at androidx.room.RoomOpenHelper.onUpgrade(RoomOpenHelper.java:103)
- i.e. replicating the failure encountered
Steps 1-2 were rerun after uninstalling the App and using the code as per V1 (to demonstrate the entire process from scratch)(rerunning with the .addMigrations commented out or removed would overcome the issue)
The changes as per step 3 were applied BUT ADDITONALLY the .addMigrations line in the database build was commented out.
- 該應用程式不會崩潰。資料庫檢查器在新插入的行中顯示修改后的模式和適當的資料(另外 2 個添加的列為空):-

uj5u.com熱心網友回復:
解決上述問題所需要的只是清理專案和重建。我想舊模式不知何故仍在記憶體中,因此崩潰。
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標籤:安卓 sqlite android-room
