public void onCreate(SQLiteDatabase db) {
    db.execSQL("create table users(id int(2) primary key,name varchar(20),last_name varchar(20),email varchar(40),password varchar(16))");
    db.execSQL("create table books(id int(10) primary key,name varchar(20),type varchar(20),editorial varchar(20),año date,author varchar(40),stock int (2))");
}

private void books_default(){
    AdminSQLiteOpenHelper admin = new
    AdminSQLiteOpenHelper(getApplicationContext(),"books",null,1);
    SQLiteDatabase bd = admin.getWritableDatabase();
    cursor = bd.rawQuery("INSERT INTO books (name,author) values ('Quijote','Cervantes')",null);
    Toast.makeText(getApplicationContext(),"Libros Creados" ,
    Toast.LENGTH_SHORT).show();
    bd.close();
    cursor.close();
    createBookList();

}

private void createBookList() {
    booksList = new ArrayList<>();
    Books item;
    AdminSQLiteOpenHelper admin = new AdminSQLiteOpenHelper(getApplicationContext(),"books",null,1);
    SQLiteDatabase bd = admin.getReadableDatabase();
    String q = "SELECT name,author FROM books";
    cursor1 = bd.rawQuery(q,null);


    if (cursor1.moveToFirst()){
        do {
            item = new Books();
            item.setBookName(cursor1.getString(0));
            item.setAuthor(cursor1.getString(1));
            booksList.add(item);
        } while (cursor1.moveToNext());
        cursor1.close();
        bd.close();
    }else{
        Toast.makeText(getApplicationContext(),"No hay libros" , Toast.LENGTH_SHORT).show();
        bd.close();
    }


}