Caused by: android.database.sqlite.SQLiteException: Can't downgrade database from version 2 to 1

[lxw0109]

It works well when no database upgrades. But I got the following errors after upgrading the database(by dbHelper = new MyDatabaseHelper(this, "BookStore.db", null, 2)):
11-14 09:57:08.108 23201-23201/com.xlab.iscas.databasetest E/AndroidRuntime: FATAL EXCEPTION: main java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xlab.iscas.databasetest/com.xlab.iscas.databasetest.AndroidDatabaseManager}: android.database.sqlite.SQLiteException: Can't downgrade database from version 2 to 1 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2122) at android.app.ActivityThread.access$600(ActivityThread.java:140) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1228) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4895) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761) at dalvik.system.NativeStart.main(Native Method) Caused by: android.database.sqlite.SQLiteException: Can't downgrade database from version 2 to 1 at android.database.sqlite.SQLiteOpenHelper.onDowngrade(SQLiteOpenHelper.java:361) at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:255) at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164) at com.xlab.iscas.databasetest.MyDatabaseHelper.getData(MyDatabaseHelper.java:67) at com.xlab.iscas.databasetest.AndroidDatabaseManager.onCreate(AndroidDatabaseManager.java:246) at android.app.Activity.performCreate(Activity.java:5163) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2061) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2122)  at android.app.ActivityThread.access$600(ActivityThread.java:140)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1228)  at android.os.Handler.dispatchMessage(Handler.java:99)  at android.os.Looper.loop(Looper.java:137)  at android.app.ActivityThread.main(ActivityThread.java:4895)  at java.lang.reflect.Method.invokeNative(Native Method)  at java.lang.reflect.Method.invoke(Method.java:511)  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)  at dalvik.system.NativeStart.main(Native Method) 
Does anybody help? :)

[sanathp]

Does your helper override downgrade method ?

Check this for more info
http://stackoverflow.com/questions/24053786/cant-downgrade-database-from-version-2-to-1-even-after-fresh-install-and-re-run