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QUESTION
I'm a student learning about database design and currently learning about the relationships of - one-to-one, one-to-many, many-to-many. I understand the concept well enough, but feel like I'm lacking experience/information on how it would be implemented in a real production scenario.
My question is this
If I have a blog website with a Blog Post as an entity and comments for each blog post, how would you handle the comments in the database?`
Would you use a one-to-many relationship and just store all the comments in a single table. Then link those comments to each blog post and user who created it?
What if each comment had a sub-comment? Would you create a separate table for sub-comments and link it to a single comment? Would that cause too much overhead and confusion within the DB itself?
I get the concepts and all, but don't understand best practices for handling what seems like basic stuff.
Thanks in advance!
...ANSWER
Answered 2021-Jun-15 at 16:06The simplest solution is to stick with a one-to-many relationship. Use one table and store one comment per row, with references to the post and the comment author, and a timestamp so you can sort the comments chronologically.
You seem uncertain about whether you need a "threaded comment" hierarchy. This is more complex, so if you don't need it, don't bother.
If you do need to show comment threads, then you should learn about running recursive queries in MySQL 8.0: https://dev.mysql.com/doc/refman/8.0/en/with.html#common-table-expressions-recursive
You still only need one table. Don't create a second table for sub-comments. Just store comments like in your one-to-many example, but each comment may link to its "parent" comment when it is a reply.
Another solution that many sites use is to skip implementing their own comment system, and just embed a comment service like Disqus. That's likely to be much more reliable and safe than yours. But if you're doing this as a learning exercise, that's worthwhile too.
QUESTION
I am writing a program in python to have a user input multiple websites then request and scrape those websites for their titles and output it. However, when the program surpasses 8 websites the program crashes every time. I am not sure if it is a memory problem, but I have been looking all over and can't find any one who has had the same problem. The code is below (I added 9 lists so all you have to do is copy and paste the code to see the issue).
...ANSWER
Answered 2021-Jun-15 at 19:45To avoid the page from crashing, add the user-agent header to the headers= parameter in requests.get(), otherwise, the page thinks that your a bot and will block you.
QUESTION
I have events which is pulled from redux, and if the events array contains data, then updateData will be used to filter events into the state var data.
I have data and events both added to the dependency array as talked about here. but I'm still getting this error:
ANSWER
Answered 2021-Jun-15 at 18:54Because you are executing useEffect callback whenever data changes and you are changing data in useEffect callback.
Remove data as dependency.
Use this code to fix it
QUESTION
WWDC21 introduces Swift 5.5, with async/await. Following the Explore structured concurrency in Swift and Meet async/await in Swift WWDC21 sessions, I'm trying to use the async let function.
Here's my Playground code:
...ANSWER
Answered 2021-Jun-11 at 00:14My advice would be: don't try this in a playground. Playgrounds aren't ready for this stuff yet. Your code compiles and runs fine in a real project. Here's an example:
QUESTION
I want to use firebase auth for my android and ios applications with custom backend. So I need some way of authentication for api calls from mobile apps to the backend.
I was able to find following guide in firebase documentation which suggests to sent firebase id token to my backend and validate it there with firebase Admin SDK. https://firebase.google.com/docs/auth/admin/verify-id-tokens
But this approach does not seem to be a security best practice. For example here https://auth0.com/blog/why-should-use-accesstokens-to-secure-an-api/ it is said that for API access one should use access tokens rather than id tokens.
Are there any good pattern for using firebase auth with my backend?
...ANSWER
Answered 2021-Jun-15 at 15:02firebaser here
Firebase itself passes the ID token with each request, and then uses that on the server to identify the user and to determine whether they're authorized to perform the operation. This is a common (I'd even say idiomatic) approach to authentication and authorization, and if there's a security risk that you've identified in it, we'd love to hear about it on https://www.google.com/about/appsecurity/
From reading the blog post it seems the author is making a distinction between authentication (the user proving their identify) and authorization (them getting access to certain resources based on that identity), but it'd probably be best to ask the author for more information on why that would preclude passing an ID token to identify the user.
QUESTION
I am a beginner learning the Django RestFramework. I had created this for an blog post page for my project. I looked through different tutorials and posts but couldn't really figure out. Can you help me converting this functional view into a class view? Thanks
...ANSWER
Answered 2021-Jun-15 at 14:30from rest_framework import generics
class PostList(generics.ListCreateAPIView):
queryset = Post.objects.all()
serializer_class = PostSerializer
class PostDetail(generics.RetrieveUpdateDestroyAPIView):
queryset = Post.objects.all()
serializer_class = PostSerializer
QUESTION
I have a table with posts that can have multiple categories, and a table with categories that can have multiple posts. models.py:
...ANSWER
Answered 2021-Jun-15 at 11:16This might help you:
QUESTION
I have a navbar and sidebar component in my nextjs app.
In my index component I'm using useState to show and hide sidebar on mobile device.
It works perfectly fine but I want to add animation when user clicks on hamburger menu, the sidebar should be animated left to right and when clicked on close icon it should go back to right to left. FYI I am using tailwind css.
Here's the code:
indexjs file:
ANSWER
Answered 2021-Jun-15 at 06:24Can you try this?
QUESTION
Base.html
...ANSWER
Answered 2021-Jun-15 at 04:11Typo.
In the base.html, you've named the block "content". In index.html, you've called it "contend".
It would be nice if Django threw an error when this sort of thing happens - but I think the main reason it doesn't is for adaptability. At a glance it seem you're doing everything else correctly though.
QUESTION
I am trying to follow this tutorial here - https://juliasilge.com/blog/xgboost-tune-volleyball/
I am using it on the most recent Tidy Tuesday dataset about great lakes fishing - trying to predict agency based on many other values.
ALL of the code below works except the final row where I get the following error:
...ANSWER
Answered 2021-Jun-15 at 04:08If we look at the documentation of last_fit() We see that split must be
An rsplit object created from `rsample::initial_split().
You accidentally passed the cross-validation folds object stock_folds into split but you should have passed rsplit object stock_split instead
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