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我想知道如何使用MongoAlchemy關於嵌入式文檔操作。 但我沒有找到任何有關這些文件。 任何人都可以給我一些幫助嗎?MongoAlchemy查詢嵌入式文檔
下面是演示代碼:
#!/usr/bin/python
# -*- coding: utf-8 -*-
from flask import Flask
from flaskext.mongoalchemy import MongoAlchemy
app = Flask(__name__)
app.config['DEBUG'] = True
app.config['MONGOALCHEMY_DATABASE'] = 'book'
db = MongoAlchemy(app)
class Comment(db.Document):
user_id = db.StringField(db_field='uid')
posted = db.StringField(db_field='posted')
class Book(db.Document):
title = db.StringField()
author = db.StringField()
comments = db.ListField(db.DocumentField(Comment), db_field='Comments')
from mongoalchemy.session import Session
def test():
with Session.connect('book') as s:
s.clear_collection(Book)
save()
test_Book()
def save():
title = "Hello World"
author = 'me'
comment_a = Comment(user_id='user_a', posted='post_a')
comment_b = Comment(user_id='user_b', posted='post_b')
comments = [comment_a, comment_b]
book = Book(title=title, author=author, comments=comments)
book.save()
def test_Book():
book = Book.query.filter({'author':'me'}).first()
comment = book.comments[0]
comment.posted = str(book.comments[0].posted)+'_new'
book.save()
print 'change posted: Book.comments[0].posted:', book.comments[0].posted
comment_c = Comment(user_id='user_c', posted='post_c')
book.comments.append(comment_c)
book.save()
print 'append: Book.comments[2].posted:', book.comments[2].posted
query = Book.query.filter({Book.comments:{'$elemMatch':{Comment.user_id:'user_c'}}}).limit(1).first()
print 'query type:', type(query)
if __name__ == '__main__':
test()
我想查詢數據,user_id是「user_c」,只是回退一個評論,我怎麼能這樣做? 下面的這些方法是否是MongoAlchemy remommended?順便說一句,這些方法將返回整個文檔。
#query = Book.query.filter({Book.comments:{'uid':'user_c'}}).limit(1).first() #query = Book.query_class(Comment).filter(Comment.user_id == 'user_c').limit(1).first() #query = Book.query.filter({'comments':{'$elemMatch':{'uid':'user_c'}}}).limit(1).first() #query = Book.query.filter({Book.comments:{'$elemMatch':{Comment.user_id:'user_c'}}}).limit(1).first()
如何將「user_c」更改爲「user_c_new」,通過查詢找到?
- 如何刪除一個user_id爲「user_b」的評論?
謝謝!謝謝你的幫忙! – user2089487