问题
I am getting this error while running program with Room Database
Room cannot verify the data integrity. Looks like you've changed schema but forgot to update the version number.
You can simply fix this by increasing the version number.
It seems we need to update Database version, but from where we can do that in Room?
回答1:
When you first come across this message, you will most likely be working against an unreleased version of the database. If that is the case, most likely you should not increment the database version. Simply clearing app data will move you passed the exception.
If you do not increment the database (recommended):
You should clear the application's app data from Android settings. You might alternatively be able to uninstall the previous app version and then install the new version to get passed the exception. This latter approach does not work under certain conditions (such as when allow backup is enabled)
Since clearing application data always works, I take that route every time.
If you do increment the database version:
You will need to write database migration code to account for any changes to the database schema. See here for information on migration.
Alternative to writing database migration code is to call fallbackToDestructiveMigration on the Room database builder. This is probably not a good idea. Forgetting to remove this call and then forgetting to upgrade the database will result in data loss.
// Using this fallback is almost certainly a bad idea
Database database = Room.databaseBuilder(context, Database.class, DATABASE_NAME)
.fallbackToDestructiveMigration()
.build();
Again, neither incrementing the database version nor falling back to destructive migration is necessary if the previous database schema is not live in the wild.
回答2:
By default Android manifest have android:allowBackup="true", Which allow apps to persist their SQLite DB on reinstallation.
Suppose your DATABASE_VERSION was initially 3 and then you decide to reduce DB version from 3 to 1.
@Database(entities = {CallRecording.class}, version = DATABASE_VERSION)
public abstract class AppDatabase extends RoomDatabase {
public abstract RecordingDAO recordingDAO();
// static final Migration MIGRATION_1_2 = new Migration(1, 2) {
// @Override
// public void migrate(SupportSQLiteDatabase database) {
// // Since we didn't alter the table, there's nothing else to do here.
// }
// };
}
You can achieve it like this
- Clear App data from Setting. This will remove older DB(DATABASE_VERSION =3)from phone
- Uninstall your App
- Reduce DATABASE_VERSION version to 1
- Build and Reinstall Your App
Its a good practise to keep DATABASE_VERSION as constant.
回答3:
Its Very simple as shown in log
Looks like you've changed schema but forgot to update the version number.
You can simply fix this by increasing the version number.
Simple go to your Database class and upgrade your DB version by increasing 1 from current.
回答4:
Aniruddh Parihar 's answer gave me a hint and it solved.
Search for a class where you have extended RoomDatabase. There you will find version like below :
@Database(entities = {YourEntity.class}, version = 1)
just increase the version and problem is solved.
回答5:
android:allowBackup="true" inside AndroidManifest.xml prevents the data from being cleared even after the app is uninstalled.
Add this to your manifest:
android:allowBackup="false"
and reinstall the app.
Note: Make sure you change it back to true later on if you want auto backups.
Another solution:
Check the identityHash of your old json file and the new json file in apps\schema folder.
If the identityHash is different, it will give that error. Find out what you have changed by comparing both json files if you don't want to change anything.
Make sure you have exportSchema = true.
@Database(entities = {MyEntity.class, ...}, version = 2, exportSchema = true)
json schema file:
"formatVersion": 1,
"database": {
"version": 2,
"identityHash": "53cc5ef34d2ebd33c8518d79d27ed012",
"entities": [
{
code:
private void checkIdentity(SupportSQLiteDatabase db) {
String identityHash = null;
if (hasRoomMasterTable(db)) {
Cursor cursor = db.query(new SimpleSQLiteQuery(RoomMasterTable.READ_QUERY));
//noinspection TryFinallyCanBeTryWithResources
try {
if (cursor.moveToFirst()) {
identityHash = cursor.getString(0);
}
} finally {
cursor.close();
}
}
if (!mIdentityHash.equals(identityHash) && !mLegacyHash.equals(identityHash)) {
throw new IllegalStateException("Room cannot verify the data integrity. Looks like"
+ " you've changed schema but forgot to update the version number. You can"
+ " simply fix this by increasing the version number.");
}
}
回答6:
In my case android:allowBackup="false" making it from true to false worked, as this has given me nightmares before as well, this is the weirdest thing why is this setting enabled by default!
回答7:
This issue occurs mostly in development.
If you change your schema i.e., rename/add/modify your class containing table entity the integrity between exiting db in your previous build conflicts with new build.
clear the app data or install new build after uninstalling the previous build.
Now, The old db won't conflict with the newer one.
回答8:
In my case I had an AppDatabase class.
@Database(entities = {GenreData.class, MoodData.class, SongInfo.class,
AlbumsInfo.class, UserFolderListsData.class, UserPlaylistResponse.PlayLists.class, InternetConnectionModel.class}, version = 3, exportSchema = false)
I updated this version number and it solved the problem. Problem arose because i had added a property in SongInfo class and forgot to update the version number.
Hope it helps someone.
回答9:
1:- It seems we need to update database version (increment by 1)
2nd Uninstall the app or Clear app data
回答10:
If you are upgrading Room version to 1.0.0-alpha9 from old version then please visit below article. Very Good Article for Migrate from old version to 1.0.0-alpha9 version.
https://medium.com/@manuelvicnt/android-room-upgrading-alpha-versions-needs-a-migration-with-kotlin-or-nonnull-7a2d140f05b9
In Room New Version 1.0.0-alpha9 Room adds support for the NOT NULL constraint.
That is going to change the schema that Room generates. Because it changes the schema, it also changes the identityHash of the DB and that is used by Room to uniquely identify every DB version. Therefore, we need a migration
回答11:
In My case ContentProvider and room database work together so first remove all callback of ContentProvider all over the application with database class which extends SqlLiteOpenHelper Class
回答12:
In my case i was using a transaction inside the migration and Room could not update the hash using a Migration Helper
@get:Rule
val migrationTestHelper: MigrationTestHelper =
MigrationTestHelper(InstrumentationRegistry.getInstrumentation(),
C2GDatabase::class.java.canonicalName,
FrameworkSQLiteOpenHelperFactory())
/* Testing method throws error*/
db = migrationTestHelper.runMigrationsAndValidate(C2GDatabase.DB_NAME,
3,
false,
C2GDatabase.Migration_1_2(),
C2GDatabase.Migration_2_3())
override fun migrate(database: SupportSQLiteDatabase) {
/**
Error
database.beginTransaction()
**/
database.execSQL("PRAGMA foreign_keys=off;")
database.execSQL("ALTER TABLE user RENAME TO user_old;")
database.execSQL("CREATE TABLE user ( id_user INTEGER PRIMARY KEY AUTOINCREMENT, external_id INTEGER NOT NULL;")
database.execSQL("INSERT INTO user ( id_user, external_id ) " +
" SELECT id_user, external_id" +
" FROM user_old;")
database.execSQL("CREATE UNIQUE INDEX idx_unique_user ON user (external_id);")
database.execSQL("PRAGMA foreign_keys=on;")
database.execSQL("DROP TABLE user_old;")
//database.endTransaction()
}
回答13:
On android phone:
Uninstall the app or Clear app data
To delete app data: Go settings -> Apps -> Select your app -> Storage -> Clear data
The uninstall (and re-install) not works in every case, so try clear data!
回答14:
I just had a similar issue in an espresso test and the only thing that fixed it was clearing data and also uninstalling the androidx test apks like:
adb uninstall androidx.test.orchestrator
adb uninstall androidx.test.services
回答15:
@Database(entities = {Tablename1.class, Tablename2.class}, version = 3, exportSchema = false)
Change the version number in your RoomDatabase class. Increment the version number.
回答16:
If increasing schema version didn't work with you, provide migration of your database. To do it you need to declare migration in database builder:
Room.databaseBuilder(context, RepoDatabase.class, DB_NAME)
.addMigrations(FROM_1_TO_2)
.build();
static final Migration FROM_1_TO_2 = new Migration(1, 2) {
@Override
public void migrate(final SupportSQLiteDatabase database) {
database.execSQL("ALTER TABLE Repo
ADD COLUMN createdAt TEXT");
}
};
回答17:
In my case I tried all of the above. Nothing seemed to work so the solution for me was simply setting android:allowBackup="false", install the app then set it back to true
Hope it helps others :)
来源：https://stackoverflow.com/questions/44197309/room-cannot-verify-the-data-integrity