SQLite database for books

First, my Book object:

public class Book {

    public static final String TABLE_NAME = "BOOK";
    public static final String COLUMN_ID = "ID";
    public static final String COLUMN_TITLE = "TITLE";

    private long id;
    private String title;

    public Book(String title) {
        this.id = -1;
        this.title = title;
    }

    public Book(long id, String title) {
        this.id = id;
        this.title = title;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getTitle() {
        return this.title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

My Database helper:

public class DatabaseHelper extends SQLiteOpenHelper {
    private volatile SQLiteDatabase mDatabase;
    private Context mContext;

    private static final String DB_NAME = "data.db";
    private static final int DB_VERSION = 1;

    public DatabaseHelper(Context context) {
        super(context.getApplicationContext(), DB_NAME, null, DB_VERSION);
        mContext = context.getApplicationContext();
    }

    private synchronized void open() throws SQLException {
        mDatabase = getWritableDatabase();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        DatabaseSetup.createTables(db);
    }

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

    }

    //********CRUD OPERATIONS************

    public synchronized long createBook(Book book) {
        open(); //opens DB
        ContentValues values = new ContentValues();
        values.put(Book.COLUMN_TITLE, book.getTitle());
        long id = mDatabase.insertWithOnConflict(Book.TABLE_NAME, null, values, SQLiteDatabase.CONFLICT_IGNORE);
        close(); //closes DB
        return id;
    }

    public synchronized Book getBookById(long id) {
        open(); //opens DB
        Cursor cursor = mDatabase.query(
                Book.TABLE_NAME, // table
                new String[]{Book.COLUMN_ID, Book.COLUMN_TITLE}, // column names
                Book.COLUMN_ID + " = ?", // where clause
                new String[]{id + ""}, // where params
                null, // groupby
                null, // having
                null);  // orderby

        Book book = null;

        if (cursor != null && cursor.getCount() > 0) {
            cursor.moveToFirst();
            String title = getStringFromColumnName(cursor, Book.COLUMN_TITLE);
            book = new Book(id, title);
            cursor.close();
        }
        close(); //closes DB
        return book;
    }

    public synchronized long updateBook(Book book) {
        open(); //opens DB
        long bookId = book.getId();
        ContentValues values = new ContentValues();
        values.put(Book.COLUMN_TITLE, book.getTitle());
        long numUpdated = mDatabase.updateWithOnConflict(
                Book.TABLE_NAME, // table
                values, // values
                Book.COLUMN_ID + " = ?", // where clause
                new String[]{bookId + ""}, // where params
                SQLiteDatabase.CONFLICT_IGNORE);
        close(); //closes DB
        return numUpdated;
    }

    public synchronized void deleteBook(Book book) {
        open(); //opens DB
        long bookId = book.getId();
        mDatabase.delete(
                Book.TABLE_NAME, // table
                Book.COLUMN_ID + " = ?", // where clause
                new String[]{bookId + ""}); // where params
        close(); //closes DB
    }

    //********HELPER FUNCTIONS************

    public static String getStringFromColumnName(Cursor cursor, String columnName) {
        int columnIndex = cursor.getColumnIndex(columnName);
        return cursor.getString(columnIndex);
    }
}

And my Database setup class which handles create-table queries

public class DatabaseSetup {

    //create-table queries

    public static final String CREATE_TABLE_BOOK_STRING =
            "CREATE TABLE " + Book.TABLE_NAME + " ("
                    + Book.COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                    + Book.COLUMN_TITLE + " TEXT NOT NULL)";

    public static void createTables(SQLiteDatabase db) {
        db.execSQL(CREATE_TABLE_BOOK_STRING);
    }
}

1. Is it considered a good idea to open and close the database in every CRUD function like I am doing? I do it this way because even if I were to just open the database in, for example, an onResume() call in an Activity, there is no guarantee the connection will still be open by the time I invoke a CRUD operation elsewhere in the Activity.

2. Do I need to be doing anything else to verify that the database is open / safe to perform operations on?

3. Is it even necessary to call close()?

4. Is it bad practice for me to be putting the table name / field names in the Book class?

5. Should I be putting the CRUD operations in their own separate class, e.g. public class BookCrudHandler?

6. Should I be putting the id in the Book class (so that I have some relationship between the object and the row in the database), or should I have some other kind of data structure that maps POJOs to their corresponding IDs in the database that I reference as a lookup?

7. Anything else / any comments / any practices I am missing that I should be using?