Android: Standalone login with SQLiteOpenHelper

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

/**
 * Created by Chandra on 31-10-2015.
 */
public class LoginSQLiteHelper extends SQLiteOpenHelper {

    public static final String TABLE_NAME = "table_login";
    public static final String COLUMN_ID = "_id";
    public static final String COLUMN_USER_EMAIL = "user_email";
    public static final String COLUMN_USER_PWD = "user_pwd";
    public static final String COLUMN_USER_NAME = "user_name";
    public static final String COLUMN_USER_NO = "user_no";

    private static final String DATABASE_NAME = "login.db";
    private static final int DATABASE_VERSION = 1;

    // Database creation sql statement
    private static final String SQL_CREATE_ENTRIES = "CREATE TABLE "
            + TABLE_NAME + "(" + COLUMN_ID + " INTEGER PRIMARY KEY, "
            + COLUMN_USER_EMAIL + " TEXT, "
            + COLUMN_USER_PWD + " TEXT, "
            + COLUMN_USER_NAME + " TEXT, "
            + COLUMN_USER_NO + " TEXT)" ;

    public LoginSQLiteHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase database) {
        database.execSQL(SQL_CREATE_ENTRIES);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.w(LoginSQLiteHelper.class.getName(),
                "Upgrading database from version " + oldVersion + " to "
                        + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);
    }
}



/**
 * Created by Chandra on 31-10-2015.
 */
public class LoginDataSource {

    private static Context mContext;
    private SQLiteDatabase database;
    private LoginSQLiteHelper dbHelper;

    private String[] allColumns = {LoginSQLiteHelper.COLUMN_ID,
            LoginSQLiteHelper.COLUMN_USER_EMAIL,
            LoginSQLiteHelper.COLUMN_USER_PWD,
            LoginSQLiteHelper.COLUMN_USER_NAME,
            LoginSQLiteHelper.COLUMN_USER_NO};

    private static LoginDataSource ourInstance = null;

    public static LoginDataSource getInstance() {
        if (null == ourInstance) {
            ourInstance = new LoginDataSource();
        }
        return ourInstance;
    }

    public void setAppContext(Context context) {
        mContext = context;
    }

    private LoginDataSource() {
    }

    public void open() throws SQLException {
        dbHelper = new LoginSQLiteHelper(mContext);
        database = dbHelper.getWritableDatabase();
    }

    public void close() {
        dbHelper.close();
    }

    public List<UserInfo> getAllEntry() {
        List<UserInfo> entryList = new ArrayList<>();

        Cursor cursor = database.query(LoginSQLiteHelper.TABLE_NAME,
                allColumns, null, null, null, null, null);
        cursor.moveToFirst();
        while (!cursor.isAfterLast()) {
            UserInfo entry = UserManager.getInstance().cursorToEntry(cursor);
            entryList.add(entry);
            cursor.moveToNext();
        }
        cursor.close();
        return entryList;
    }

    public UserInfo createEntry(String email, String pwd, String name,
                                String no) {
        ContentValues values = new ContentValues();
        values.put(LoginSQLiteHelper.COLUMN_USER_EMAIL, email);
        values.put(LoginSQLiteHelper.COLUMN_USER_PWD, pwd);
        values.put(LoginSQLiteHelper.COLUMN_USER_NAME, name);
        values.put(LoginSQLiteHelper.COLUMN_USER_NO, no);
        long insertId = database.insert(LoginSQLiteHelper.TABLE_NAME, null, values);

        Cursor cursor = database.query(LoginSQLiteHelper.TABLE_NAME,
                allColumns, LoginSQLiteHelper.COLUMN_ID + " = " + insertId, null,
                null, null, null);
        cursor.moveToFirst();
        UserInfo newEntry = UserManager.getInstance().cursorToEntry(cursor);
        cursor.close();
        return newEntry;
    }

    public void deleteEntry(UserInfo entry) {
        String id = entry.getEmail();
        database.delete(LoginSQLiteHelper.TABLE_NAME, LoginSQLiteHelper.COLUMN_USER_EMAIL
                + " = " + id, null);
    }

    public Cursor login(String userId, String password) {
        Cursor myCursor = database.query(LoginSQLiteHelper.TABLE_NAME,
                new String[]{LoginSQLiteHelper.COLUMN_USER_EMAIL, LoginSQLiteHelper.COLUMN_USER_PWD,
                        LoginSQLiteHelper.COLUMN_USER_NAME, LoginSQLiteHelper.COLUMN_USER_NO},
                LoginSQLiteHelper.COLUMN_USER_EMAIL + "='" + userId + "' AND " +
                        LoginSQLiteHelper.COLUMN_USER_PWD + "='" + password + "'", null, null, null, null);

        if (myCursor != null) {
            myCursor.moveToFirst();
        }
        return myCursor;
    }

    public Cursor getUserInfo(String userId) {
        Cursor myCursor = database.query(LoginSQLiteHelper.TABLE_NAME,
                new String[]{LoginSQLiteHelper.COLUMN_USER_EMAIL,
                        LoginSQLiteHelper.COLUMN_USER_NAME, LoginSQLiteHelper.COLUMN_USER_NO},
                LoginSQLiteHelper.COLUMN_USER_EMAIL + "='" + userId + "'", null, null, null, null);

        if (myCursor != null) {
            myCursor.moveToFirst();
        }
        return myCursor;
    }
}