Cannot open my database on the android device, but can on the emulator

问题

Can anyone explain what's the problem? I developed my application which uses my own database. All worked fine, but in one day I began to receive the error at

long rowsCount = DatabaseUtils.queryNumEntries(myDataBase, table);

The error is

android.database.sqlite.SQLiteDatabaseCorruptException: database disk image is malformed: , while compiling: SELECT count(*) FROM words

The strangest in that I receive the error only on my device (lg p500), and the program works fine on the emulator.

My code related to the database:

dbHelper = new MySQLiteHelper(context);
    try {
        dbHelper.createDataBase();
    }catch(IOException ioe) 
    {
        throw new Error("Unable to create database");
    }
...
dbHelper.openDataBase();
long tableSize = dbHelper.countTableRows(MySQLiteHelper.TABLE_WORDS); //The error appears
...

MySQLiteHelper code:

public class MySQLiteHelper extends SQLiteOpenHelper {

private static final String DATABASE_NAME = "words.db";
private static final int DATABASE_VERSION = 1;
private static final String DB_PATH = "/data/data/ru.my.program/databases";
public static final String TABLE_WORDS = "words";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_WORD = "word";
private final Context myContext;

public SQLiteDatabase myDataBase;

public MySQLiteHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
    myContext = context;
}

@Override
public void onCreate(SQLiteDatabase database) {
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {  
}

public void createDataBase() throws IOException{         
    boolean dbExist = checkDataBase(); 
    if(dbExist){
        //do nothing - database already exist
    }else{ 
        //By calling this method and empty database will be created into the default system path
        //of your application so we are gonna be able to overwrite that database with our database.
        this.getReadableDatabase(); 
        this.close();
        try 
        {
            copyDataBase(); 
        }
        catch(IOException e)
        { 
            throw new Error("Error copying database"); 
        }
    }
}

private boolean checkDataBase(){    
    File dbFile = new File(DB_PATH + "/" + DATABASE_NAME);
    return dbFile.exists();

}

private void copyDataBase() throws IOException{      
    //Open your local db as the input stream
    InputStream myinput = myContext.getAssets().open(DATABASE_NAME);

    // Path to the just created empty db
    String outfilename = DB_PATH + "/" +DATABASE_NAME;

    //Open the empty db as the output stream
    OutputStream myoutput = new FileOutputStream("/data/data/ru.my.program/databases/words.db");

    // transfer byte to inputfile to outputfile
    byte[] buffer = new byte[1024];
    int length;
    while ((length = myinput.read(buffer))>0)
    {
        myoutput.write(buffer,0,length);
    }

    //Close the streams
    myoutput.flush();
    myoutput.close();
    myinput.close();
}

public void openDataBase() throws SQLException{
    String myPath = DB_PATH + "/" +DATABASE_NAME;
    myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS|SQLiteDatabase.OPEN_READONLY);
    Log.i(MySQLiteHelper.class.getName(), "Open DB");
}

@Override
public synchronized void close() {
    if(myDataBase != null)
            myDataBase.close();
    super.close();

}
public long countTableRows(String table)
{
    long rowsCount = DatabaseUtils.queryNumEntries(myDataBase, table);
    return rowsCount;
}

I have checked up the database on the device with the DDMS and was convinced that it is copied in a proper place and it same, as in assets.

I have checked that the database has android_metadata table with locale="ru_RU".

I have checked that I have the column "_id" in the "words" table.

I tried to remove the application folder (with the database) manually, but it hasn't helped.

I even tried to rename my application package...

回答1:

I think its your database version so can you change that database version as 3

回答2:

The problem has disappeared after I have recreated the database file. It seems that the database file should have one more table "sqlite_sequence". The table should contain two columns: name and seq. "name" for names of tables, which you have created (excluding android_metadata), "seq" for amount of rows in these tables.

来源：https://stackoverflow.com/questions/9322899/cannot-open-my-database-on-the-android-device-but-can-on-the-emulator

标签

android

database

android-emulator

malformed