【代码】SQLAlchemy的增删改查之增

淩亂°似流年 2022-04-05 15:10 186阅读 0赞

@app.route('/', methods=['get', 'post'])
    def index():
        append_form = Append()
    
        if request.method == 'POST':
            if append_form.validate_on_submit():
                author_name = append_form.au_info.data
                book_name = append_form.bk_info.data
                # 判断数据是否存在
                author = Author.query.filter_by(name=author_name).first()
                if not author:
                    try:
                        # 先添加作者
                        author = Author(name=author_name)
                        db.session.add(author)
                        db.session.commit()
                        # 再添加书籍
                        book = Book(name=book_name, author_id=author.id)
                        db.session.add(book)
                        db.session.commit()
                    except Exception as e:
                        db.session.rollback()
                        print e
                        flash("数据添加错误")
                else:
                    book_names = [book.name for book in author.books]
                    if book_name in book_names:
                        flash('该作者已存在相同的书名')
                    else:
                        try:
                            book = Book(name=book_name, author_id=author.id)
                            db.session.add(book)
                            db.session.commit()
                        except Exception as e:
                            db.session.rollback()
                            print e
                            flash('数据添加错误')
            else:
                flash('数据输入有问题')
    
        authors = Author.query.all()
        books = Book.query.all()
        return render_template('test2.html', authors=authors, books=books, append_form=append_form)