Question

I am working on android application.My client provides me a data base which is some what large .It is almost 2.3Mb. Initially i don’t know how to use existing data base i followed this tutorial tutorial

for accessing the existing database.But i got error.Here i am wondering how to access this type of large database . Can any one help me.

Here i have my DataBaseHelper class.

public class DataBaseHelper extends SQLiteOpenHelper {

// The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.example.readdatabase/databases/";

private static String DB_NAME = "categories.sqlite";

private SQLiteDatabase myDataBase;

private final Context myContext;

public DataBaseHelper(Context context) {

    super(context, DB_NAME, null, 1);
    this.myContext = context;
}

public void createDataBase() throws IOException {

    boolean dbExist = checkDataBase();

    if (dbExist) {
        // do nothing - database already exist
    } else {

        this.getReadableDatabase();

        try {

            copyDataBase();

        } catch (IOException e) {

            throw new Error("Error copying database");

        }
    }

}

/**
 * Check if the database already exist to avoid re-copying the file each
 * time you open the application.
 * 
 * @return true if it exists, false if it doesn't
 */
private boolean checkDataBase() {

    SQLiteDatabase checkDB = null;

    try {
        String myPath = DB_PATH + DB_NAME;
        checkDB = SQLiteDatabase.openDatabase(myPath, null,
                SQLiteDatabase.OPEN_READONLY);

    } catch (SQLiteException e) {

        // database does't exist yet.

    }

    if (checkDB != null) {

        checkDB.close();

    }

    return checkDB != null ? true : false;
}

/**
 * Copies your database from your local assets-folder to the just created
 * empty database in the system folder, from where it can be accessed and
 * handled. This is done by transfering bytestream.
 * */
private void copyDataBase() throws IOException {

    // Open your local db as the input stream
    InputStream myInput = myContext.getAssets().open(DB_NAME);

    // Path to the just created empty db
    String outFileName = DB_PATH + DB_NAME;

    // Open the empty db as the output stream
    OutputStream myOutput = new FileOutputStream(outFileName);

    // transfer bytes from the inputfile to the 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 {

    // Open the database
    String myPath = DB_PATH + DB_NAME;
    myDataBase = SQLiteDatabase.openDatabase(myPath, null,
            SQLiteDatabase.OPEN_READONLY);

}

@Override
public synchronized void close() {

    if (myDataBase != null)
        myDataBase.close();

    super.close();

}

@Override
public void onCreate(SQLiteDatabase db) {

}

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

}

public Cursor performTransaction(String query) {

    Cursor cur = myDataBase.rawQuery(query, null);

    return cur;
}

}

Here is my main class

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    DataBaseHelper db = new DataBaseHelper(this);
    try {
        db.createDataBase();
    } catch (IOException e) {
        e.printStackTrace();
    }
    db.openDataBase();

    String query = "select * from PrayerInfo";
    Cursor cursor = db.performTransaction(query);
    System.out.println(cursor.getColumnCount());
}

}

It works fine in Android 2.3 and higher versions .but it does not work on lower versions .I got the error like.can any one help me

java.lang.Error: Error copying database at com.example.readdatabase.DataBaseHelper.createDataBase(DataBaseHelper.java:48) at com.example.readdatabase.MainActivity.onCreate(MainActivity.java:18)

Answer 1

This library might be useful to you: Android SQLite Asset Helper

Note that you won’t be able to use the original database directly but only a copy, so you will have some wasted space.

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Another solution might to convert the original database to SQL (which can be compressed in a zip file), and play the script in SqliteOpenHelper.onCreate method.

See this link for a way to do it: How do I dump the data of some SQLite3 tables?