You have to connect the two objects explicitly to create the relationship. For example:
author.books.append(book)
Frage
My app looks like:
app = Flask(__name__, template_folder='templates')
app.config.from_object('config')
db = SQLAlchemy(app)
My SQLAlchemy classes look like:
connections = db.Table('connections', db.metadata,
db.Column('book_id', db.Integer, db.ForeignKey('books.id')),
db.Column('author_id', db.Integer, db.ForeignKey('authors.id'))
)
class Author(db.Model):
__tablename__ = 'authors'
__searchable__ = ['a_name']
__table_args__ = {'sqlite_autoincrement': True,}
id = db.Column(db.Integer, primary_key=True)
a_name = db.Column(db.String(80), unique=True)
def __repr__(self):
return unicode(self.a_name)
class Book(db.Model):
__tablename__ = 'books'
__searchable__ = ['b_name']
__table_args__ = {'sqlite_autoincrement': True,}
id = db.Column(db.Integer, primary_key=True)
b_name = db.Column(db.String(80))
authors = db.relationship('Author', secondary=lambda: connections,
backref=db.backref('books'))
def __repr__(self):
return unicode(self.b_name)
As you can see. The SQLAlchemy classes are many-to-many db structure. What I need is to add book`s title and ahthors names at the same html-form and save it at my database.
@app.route('/add', methods=['GET', 'POST'])
def add_book():
if request.method == "POST":
author = Author(a_name = request.form['author'])
book = Book(b_name = request.form['book'])
db.session.add(author)
db.session.add(book)
db.session.commit()
return redirect(url_for('show_books'))
But something is missing here. These new created book and author do not correlate to each other. They do not have authors-books relationship. What statement I need to add to implement this relationship?
Lösung
You have to connect the two objects explicitly to create the relationship. For example:
author.books.append(book)