Flask-SQLAlchemy多对多插入 [英] Flask-SQLAlchemy Many to Many Insert
问题描述
我已经尝试了上述建议，但是在插入带有标签的新帖子时，在多对多属性的追加中继续收到以下错误.
任何方向将不胜感激！
1:06:22 PM web.1 | post.tags.append(post_tag)
11:06:22 PM web.1 |附上文件"/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/collections.py"，第1072行
11:06:22 PM web.1 |item = __set(自身，item，_sa_initiator)
11:06:22 PM web.1 |在__set
中的文件"/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/collections.py"，第1044行11:06:22 PM web.1 |item = executor.fire_append_event(item，_sa_initiator)
11:06:22 PM web.1 |在fire_append_event中的文件"/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/collections.py"，第716行
11:06:22 PM web.1 |项目，发起人)
11:06:22 PM web.1 |在fire_append_event中的文件"/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/attributes.py"中，行936
11:06:22 PM web.1 |启动器或self._append_token或self._init_append_token())
11:06:22 PM web.1 |在第1171行"中的"/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/attributes.py"文件中，在"eject_backref_from_collection_append_event"中
11:06:22 PM web.1 |child_state，child_dict = instance_state(child)，\
11:06:22 PM web.1 |AttributeError:"BaseQuery"对象没有属性"_sa_instance_state"
Model.py
blog_tag = db.Table('post_tag'，db.Column('post_id'，db.Integer，db.ForeignKey('post.id'))，db.Column('tag_id'，db.Integer，db.ForeignKey('tag.id')))类Post(db.Model):""SQLAlchemy Post对象类""id = db.Column(db.Integer，primary_key = True)正文= db.Column(db.Text)时间戳= db.Column(db.DateTime)标题= db.Column(db.String(50))作者= db.Column(db.Integer，db.ForeignKey('user.id'))uuid = db.Column(db.String(255))标签= db.relationship('标签'，次要= blog_tag，back_populates =帖子")类Tag(db.Model):""SQLAlchemy标签对象类""id = db.Column(db.Integer，primary_key = True)name = db.Column(db.String，unique = True，nullable = False)posts = db.relationship('Post'，secondary = blog_tag，back_populates =标签") Views.py
@ console.route('/new_post'，methods = ['GET'，'POST'])@需要登录def new_post():post_form = PostForm()如果post_form.validate_on_submit():获取"标签列表，并将其转换为数组.uid = uuid.uuid4()post = Post()post.title = post_form.title.datapost.body = post_form.body.datapost.timestamp = datetime.utcnow()post.author = current_user.idpost.uuid = uid.hextag_string = post_form.tags.data标签= tag_string.split(，")用于标签中的标签:post_tag = add_tags(标签)打印post_tagpost.tags.append(post_tag)db.session.add(post)db.session.commit()flash(u创建新帖子！"，"alert-info")返回render_template('new_post.html'，title ='管理员-新帖子'，形式= post_form)def add_tags(标签):existing_tag = Tag.query.filter(Tag.name == tag.lower())如果确实将现有标签objec返回到列表"，则返回".如果exist_tag不为None:返回现存的标签别的:new_tag =标签()new_tag.name = tag.lower()返回new_tag 此:
existing_tag = Tag.query.filter(Tag.name == tag.lower())"如果确实将现有标签objec返回列表""如果exist_tag不为None:返回现存的标签 不返回 Tag ，而是返回 Query .您要 Tag.query.filter(...).one_or_none()来获取标签本身.
Flask sqlalchemy many-to-many insert data
I've tried the above advice but continue to recieve the following error on the append of a many to many attribute when inserting a new post with tags.
Any direction would be most appreciated!
1:06:22 PM web.1 | post.tags.append(post_tag)
11:06:22 PM web.1 | File "/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/collections.py", line 1072, in append
11:06:22 PM web.1 | item = __set(self, item, _sa_initiator)
11:06:22 PM web.1 | File "/home/trevor/Projects/trevorblog/venv/local /lib/python2.7/site-packages/sqlalchemy/orm/collections.py", line 1044, in __set
11:06:22 PM web.1 | item = executor.fire_append_event(item, _sa_initiator)
11:06:22 PM web.1 | File "/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/collections.py", line 716, in fire_append_event
11:06:22 PM web.1 | item, initiator)
11:06:22 PM web.1 | File "/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/attributes.py", line 936, in fire_append_event
11:06:22 PM web.1 | initiator or self._append_token or self._init_append_token())
11:06:22 PM web.1 | File "/home/trevor/Projects/trevorblog/venv/local/lib/python2.7/site-packages/sqlalchemy/orm/attributes.py", line 1171, in emit_backref_from_collection_append_event
11:06:22 PM web.1 | child_state, child_dict = instance_state(child), \
11:06:22 PM web.1 | AttributeError: 'BaseQuery' object has no attribute '_sa_instance_state'
Model.py
blog_tag = db.Table('post_tag',
db.Column('post_id', db.Integer, db.ForeignKey('post.id')),
db.Column('tag_id', db.Integer, db.ForeignKey('tag.id'))
)
class Post(db.Model):
"""SQLAlchemy Post object class"""
id = db.Column(db.Integer, primary_key=True)
body = db.Column(db.Text)
timestamp = db.Column(db.DateTime)
title = db.Column(db.String(50))
author = db.Column(db.Integer, db.ForeignKey('user.id'))
uuid = db.Column(db.String(255))
tags = db.relationship('Tag',secondary=blog_tag,
back_populates="posts")
class Tag(db.Model):
"""SQLAlchemy Tag object class"""
id=db.Column(db.Integer, primary_key=True)
name=db.Column(db.String, unique=True, nullable=False)
posts = db.relationship('Post', secondary = blog_tag,
back_populates = "tags")
Views.py
@console.route('/new_post', methods=['GET', 'POST'])
@login_required
def new_post():
post_form = PostForm()
if post_form.validate_on_submit():
"""Take the list of tags and turn them into an array"""
uid = uuid.uuid4()
post = Post()
post.title = post_form.title.data
post.body = post_form.body.data
post.timestamp = datetime.utcnow()
post.author = current_user.id
post.uuid = uid.hex
tag_string = post_form.tags.data
tags = tag_string.split(",")
for tag in tags:
post_tag = add_tags(tag)
print post_tag
post.tags.append(post_tag)
db.session.add(post)
db.session.commit()
flash (u'New Post Created!', 'alert-info')
return render_template('new_post.html',
title='Admin-New Post',
form=post_form)
def add_tags(tag):
existing_tag = Tag.query.filter(Tag.name == tag.lower())
"""if it does return existing tag objec to list"""
if existing_tag is not None:
return existing_tag
else:
new_tag = Tag()
new_tag.name = tag.lower()
return new_tag
This:
existing_tag = Tag.query.filter(Tag.name == tag.lower())
"""if it does return existing tag objec to list"""
if existing_tag is not None:
return existing_tag
does not return a Tag, but a Query. You want to Tag.query.filter(...).one_or_none() to get the tag itself.
这篇关于Flask-SQLAlchemy多对多插入的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
