text: --// add_data_to_books
  -- Migration SQL that makes the change goes here.
  INSERT INTO books(bookname,author,publish_year)
  VALUES ('Harry Potter','J.K.Rowling', '1997');
  INSERT INTO books(bookname,author,publish_year)
  VALUES ('A Song of Ice and Fire','George R. R. Martin', '1996');
  
  
  --//@UNDO
  -- SQL to undo the change goes here.
  
  
  