I have users, meetings and comments tables and I want users to be able to post comments on users profile and meetings.
I know how to make one to many relationships for users and comments tables, but I want all comments to be saved in one table and show comments on users profile and meetings.
This is my table structure:
users
id
name
comment_id
meetings
id
name
comments
id
user_id
comment
TL;DR The solution is to use polymorphic relationships which Laravel makes really easy.
IMHO I don't think that a many-to-many relationship will do the job. It would mean that:
a user can post multiple comments. Okay
a comment can belong to multiple user. Weird
a meeting can have multiple comments. Okay
a comment can belong to multiple meetings. Weird
Plus you would likely need two comments tables to achieve that. For instance a comment_user table and a comment_meeting.
The kind of relationship that would fit the most your situation is the polymorphic one. The name can be scary because it comes from ancient greek. But the concept behind the name is very simple. And Laravel makes polymorphic relationships very easy. You will certainly recognize your situation in the example given in the Laravel documentation ;)
While saving comment, also keep a field named model (or anyone you like) to identify users profile and meetings
HTH
Related
i want to create a platform by laravel 6 included classes students an masters
masters can put the student's scores and the students can see them in their profile...
there is a many to many relation between classes and masters and between student and classes too.
the masters an students are not seperated and all of them store in user table and determine by his role_id
my big issue is uploading of scores by masters... i am extremely confused
has any one any idea ?
What you might want to simplify things is an associative table of users, classes, and scores (I've drawn a diagram for you https://dbdiagram.io/d/5e9787f039d18f5553fdabb1). With this table, you can query pretty much all you could ever want.
Now all you need to do is configure privileges based on user role. A master can read from and write to all class_user_score entities where if there is a record of him being in a class, he can read and CRUD all class_user_score entities with the same classId. A student can only read class_user_score entities with his userId in them.
Unfortunately, I can't help you with the Laravel implementation (they also call an associative table a pivot table for some weird reason) since I'm more of a React, Nodejs type of guy, but I hope this at least helps you to reason about the problem.
I'm trying to figure out what is the best practice with selecting data from two related model.
I have a model (and a db table) "person" and then i have a model (and a db table) comment. There may be multiple comments for one person and comment has "person_id" column.
I have two cases in particular.
First i need to show persons profile with all his comments.
In my controller do I select the needed person through my person model and then select all the comments through my comments model? Or is it more correct for person model already return person with all comments?
I myself would guess that first option is ok.
Second case is where i need to show all latest comments with name of the person who made the comment.
So in my controller is it correct to select all latest comments from comments model and then select a person for each or them? Or is it more correct for the comments model to return comment with person name included?
In this case i would guess that second option is better. It seems really strange to first select comments and then iterate them and select a person for each of them.
So im kind of confused because case 1 and 2 seem similar but i would use different solutions for them. Which one is correct?
I've done quit a bit of programming with php/mysql on small scale personal projects. However I'm working on my first commercial app that is going to allow customers or businesses to log in and perform CRUD operations. I feel like a total noob asking this question but I have never had to do this before and cannot find any relevant information on the net.
Basically, I've created this app and have a role based system set up on my data base. The problem that I'm running into is how to separate and fetch data for the relevant businesses or groups.
I can't, for example, set my queries up like this: get all records from example table where user id = user id, because that will only return data for that user and not all of the other users that are related to that business. I need a way to get all records that where created by users of a particular business.
I'm thinking that maybe the business should have an id and I should form my queries like this: get all records from example where business id = business id. But I'm not even sure if that's a good approach.
Is there a best practice or a convention for this sort data storing/fetching and grouping?
Note:Security is a huge issue here because I'm storing legal data.
Also, I'm using the latest version of laravel 4 if that's any relevance.
I would like to hear peoples thoughts on this that have encountered this sort problem before and how they designed there database and queries to only get and store data related to that particular business.
Edit: I like to read and learn but cannot find any useful information on this topic - maybe I'm not using the correct search terms. So If you know of any good links pertaining to this topic, please post them too.
If I understand correctly, a business is defined within your system as a "group of users", and your whole system references data belonging to users as opposed to data belonging to a business. You are looking to reference data that belongs to all users who belong to a particular business. In this case, the best and most extensible way to do this would be to create two more tables to contain businesses and business-user relations.
For example, consider you have the following tables:
business => Defines a business entity
id (primary)
name
Entry: id=4, name=CompanyCorp
user => Defines each user in the system
id (primary)
name
Entry: id=1, name=Geoff
Entry: id=2, name=Jane
business_user => Links a user to a particular business
user_id (primary)
business_id (primary)
Entry: user_id=1, business_id=4
Entry: user_id=2, business_id=4
Basically, the business_user table defines relationships. For example, Geoff is related to CompanyCorp, so a row exists in the table that matches their id's together. This is called a relational database model, and is an important concept to understand in the world of database development. You can even allow a user to belong to multiple different companies.
To find all the names of users and their company's name, where their company's id = 4...
SELECT `user`.`name` as `username`, `business`.`name` as `businessname` FROM `business_user` LEFT JOIN `user` ON (`user`.`id` = `business_user`.`user_id`) LEFT JOIN `business` ON (`business`.`id` = `business_user`.`business_id`) WHERE `business_user`.`business_id` = 4;
Results would be:
username businessname
-> Geoff CompanyCorp
-> Jane CompanyCorp
I hope this helps!
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Addendum regarding "cases" per your response in the comments.
You could create a new table for cases and then reference both business and user ids on separate columns in there, as the case would belong to both a user and a business, if that's all the functionality that you need.
Suppose though, exploring the idea of relational databases further, that you wanted multiple users to be assigned to a case, but you wanted one user to be elected as the "group leader", you could approach the problem as follows:
Create a table "case" to store the cases
Create a table "user_case" to store case-user relationships, just like in the business_user table.
Define the user_case table as follows:
user_case => Defines a user -> case relationship
user_id (primary)
case_id (primary)
role
Entry: user_id=1, case_id=1, role="leader"
Entry: user_id=2, case_id=1, role="subordinate"
You could even go further and define a table with definitions on what roles users can assume. Then, you might even change the user_case table to use a role_id instead which joins data from yet another role table.
It may sound like an ever-deepening schema of very small tables, but note that we've added an extra column to the user_case relational table. The bigger your application grows, the more your tables will grow laterally with more columns. Trust me, you do eventually stop adding new tables just for the sake of defining relations.
To give a brief example of how flexible this can be, with a role table, you could figure out all the roles that a given user (where user_id = 6) has by using a relatively short query like:
SELECT `role`.`name` FROM `role` RIGHT JOIN `user_case` ON (`user_case`.`role_id` = `role`.`id`) WHERE `user_case`.`user_id` = 6;
If you need more examples, please feel free to keep commenting.
I am working on a little project where a user submits an article to MySQL, and then PHP send the post to the screen. So far so good.
Now i want to extend it to a "two level" post system, where people can comment on the articles.
The case is, i dont know how to do that.
The table i use for storing articles:
TABLE: posts
id user date avatar signature post
Should i make a new row named comments in the posts table, or should i place the comments in a seperate table? one for articles, one for comments?
All help is much appreciated.
Depends on how you use it on your website. You have to ask: "are my articles and comments essentially the same concept?" If yes, then use one table, if no, use two. On most websites articles work differently, can be categorized, editted etc., and usually need a different fields which would clutter the comments table... so in that case two tables are more reasonable. But if you conclude that on your website articles and comments are generally the same (but try to think future proof: wouldn't you need to add some article functionality in 2 months?) then you can think of articles also as of comments and have one table for them.
If you decide to merge things to one table, and you realize that you need another column to distinguish type of the post, and that some columns remain unused for some types, it is a clear warning signal you should have two tables!
This is a little subjective, but I would just set up a parent/child relationship on your posts table, make a parent_id column that is a foreign key for the id column in the same table. for extra credit, you can make it a nested set relationship which will allow you to pull the parent and all the children in one query
I have a site that scrapes all the episodes from tv.com from certain series.
So my database has a User table, a Show table, an Episode table, a Show_User table (to associate shows with users, HABTM), an Episode_Show table (to associate episodes with shows, HABTM), a Episode_User table (to associate episodes with shows, only as a way of marking them as 'watched').
Now I want to add a way of marking an episode as 'downloaded' too.
So at the moment, the Episode_User table has two fields, Episode_Id and User_Id. Should I create a new table entirely for this? Or just add a field to the Episode_User table?
I'm using CakePHP's automagic features, and don't particularly want to break it. But if I have to, I have to...
Thanks for any advice.
I don't see why you would want to create a new table for episodes a user has downloaded. To me it would make the most sense to modify the Episode_User table to have a field for watched and a field for downloaded, since it's all relating back to the same pair of entities, users and episodes.
However, any time I've stored information about a relationship between two tables in that manner, I've found that regardless of the framework I'm using, the ORM inevitably become more complicated, but I don't think there's any way around there.
With CakePHP for handling those kinds of complicated situations, read up about the model behavior, Containable. It's not very well documented in the CakePHP book, but is really quite useful in a situation where you need to use the fields in Episode_User, for example, if you needed to find all of the users that had watched a particular episode, but not downloaded it.
Also, it occurred to me, while reading your post, that you could possibly make your data model more simple by having a hasMany relationship between shows and episodes. An episode will never belong to more than one show, so your episodes table could just have another field, show_id, which related back to the show table, and you wouldn't even need the Episode_Show table.