如何在烧瓶中使用QuerySelectField? [英] how to use QuerySelectField in flask?
问题描述
这里是代码:
def possible_book():
返回Book.query.with_entities(Book.id).all()
class AuthorForm(Form):
familyname = TextField('familyname',[validators.Required()])
firstname = TextField('firstname',[validators.Required()])
book_list = QuerySelectField('book_list',query_factory = possible_book,get_label ='title',allow_blank = True)
这是模板:
< form action =method =postname =edit_authorenctype =多部分/格式数据>
{{form.hidden_tag()}}
< p>维基百科,自由的百科全书文件:{{form.firstname(value = author.firstname)}}< / p>
Nom de famille(obligatoire):{{form.familyname(value = author.familyname)}}< / p>
< p> Livre:{{form.book_list}}< / p>
< p>< input type =submitvalue =Envoyer>< / p>
< / form>
查看:
@ app.route('/ edit_author /< number>,methods = ['GET','POST'])
def edit_author(number):
if number == 'new':
author = []
else:
author = Author.query.filter_by(id = number).first()
form = AuthorForm()
如果form.validate_on_submit():
a = Author(firstname = form.firstname.data,familyname = form.familyname.data)
a.books = form.book_list.data
db.session.add(a)
db.session.commit()
return redirect('/ admin')
return render_template('edit_author.html',form = form,作者=作者)
模型(仅粘贴关联表和作者表,大部分列)
$ b $ pre $ $ $ $ $ $ $ $ $ $ author $ book $ db.table ',db.Integer,db.ForeignKey('author.id')),
d b.Column('book',db.Integer,db.ForeignKey('book.id'))
)
$ b $ class作者(db.Model):
id = db.Column(db.Integer,primary_key = True)
firstname = db.Column(db.String(64),index = True)
familyname = db.Column(db.String(120), index = True)
website = db.Column(db.String(120))
dateofbirth = db.Column(db.DateTime)
placeofbirth = db.Column(db.String(120 ))
nationality = db.Column(db.String(120))
biography = db.Column(db.Text)
photo = db.Column(db.String(120))
books = db.relationship('Book',secondary = author_book,backref = db.backref('author',lazy ='dynamic'))
我目前得到这个错误:
$ b $ pre $ UnmappedInstanceError类'sqlalchemy。 util._collections.KeyedTuple'没有映射
我真正想要的是select字段显示作者姓名和号码,并返回作者编号到应用程序(到头部的add_author函数)。
谢谢
你有两个问题:
$ b $ ol
正如Sean Vieira在他的回答中指出的那样, code> query_factory callback应该返回一个查询,而不是结果。
query_factory
回调应该返回完整的实体,在你的案例书,而不是书的ID。我相信 QuerySelectField
必须尝试使用查询的结果,就好像它们是映射对象一样,但是(作为KeyedTuple实例返回的)不是。 我认为这是编写回调函数的正确方法:
def possible_book():
return Book.query
I am trying to have a select field filled with the results of a sqlalchemy request in a flask form.
Here are the code :
def possible_book():
return Book.query.with_entities(Book.id).all()
class AuthorForm(Form):
familyname = TextField('familyname', [validators.Required()])
firstname = TextField('firstname', [validators.Required()])
book_list = QuerySelectField('book_list',query_factory=possible_book,get_label='title',allow_blank=True)
This is the template :
<form action="" method="post" name="edit_author" enctype="multipart/form-data">
{{form.hidden_tag()}}
<p>Veuillez donner son prénom (obligatoire) : {{form.firstname(value=author.firstname)}}</p>
<p>Nom de famille (obligatoire) : {{form.familyname(value=author.familyname)}}</p>
<p>Livre : {{form.book_list}}</p>
<p><input type="submit" value="Envoyer"></p>
</form>
View :
@app.route('/edit_author/<number>', methods = ['GET', 'POST'])
def edit_author(number):
if number == 'new':
author = []
else:
author = Author.query.filter_by(id = number).first()
form = AuthorForm()
if form.validate_on_submit():
a = Author(firstname= form.firstname.data, familyname= form.familyname.data)
a.books = form.book_list.data
db.session.add(a)
db.session.commit()
return redirect('/admin')
return render_template('edit_author.html', form = form, author = author)
The model (pasted only the associative table and the author table, much of the column are out of the question)
author_book = db.Table('author_book',
db.Column('author', db.Integer, db.ForeignKey('author.id')),
db.Column('book', db.Integer, db.ForeignKey('book.id'))
)
class Author(db.Model):
id = db.Column(db.Integer, primary_key = True)
firstname = db.Column(db.String(64), index = True)
familyname = db.Column(db.String(120), index = True)
website = db.Column(db.String(120))
dateofbirth = db.Column(db.DateTime)
placeofbirth = db.Column(db.String(120))
nationality = db.Column(db.String(120))
biography = db.Column(db.Text)
photo = db.Column(db.String(120))
books = db.relationship('Book', secondary=author_book,backref=db.backref('author', lazy='dynamic'))
I currently get this error :
UnmappedInstanceError: Class 'sqlalchemy.util._collections.KeyedTuple' is not mapped
What I really want is that the select field show the author name and his number, and return the author number to the app (to the function called "add_author" on the head).
Thank you.
You have two problems:
As Sean Vieira pointed out in his answer, the
query_factory
callback should return a query, not the results.The
query_factory
callback should return complete entities, in your case books, not book ids. I believe theQuerySelectField
must be trying to use the results of the query as if they are mapped objects but the ids (returned as KeyedTuple instances) are not.
I think this is the correct way to code the callback function:
def possible_book():
return Book.query
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