relationships

问题 I know this question has been asked before on Stack Overflow, but the answers aren't doing it for me in ways I can explain. My general approach was inspired by this tutorial. What I'm trying to do, is create a really simple model for friending users that creates an equivalent friendship on both ends with a single record. At the db level, I just have a 'friendships' table that just has a user_id, a friend_id, and an is_pending boolean column. In user.rb I've defined the relationship as: has

问题 I have two related problems I need help with. Problem 1: How do I model a conditional relationship? I want my data to indicate that when test CLT1's "Result" property = "High", CLT1 has relationship to Disease A. If I take a node-centric approach, I imagine that the code might look something like... (CLT 1 {Result: "High"}) -[:INDICATES] -> (Disease A) Further, when CLT1's "Result" property = "Low", CLT1 has a relationship to Disease B (CLT 1 {Result: "Low"}) -[:INDICATES] -> (Disease B)

问题 For example a list and a sublist can have many items through a model called list_items. Here are the models class List < ActiveRecord::Base has_many :sublists has_many :list_items has_many :items, through: :list_items end class Sublist < ActiveRecord::Base belongs_to :list has_many :list_items has_many :items, through: :list_items end class Item < ActiveRecord::Base has_many :list_items has_many :lists,through: :list_items has_many :sublists, through: :list_items end class ListItem <

问题 For example a list and a sublist can have many items through a model called list_items. Here are the models class List < ActiveRecord::Base has_many :sublists has_many :list_items has_many :items, through: :list_items end class Sublist < ActiveRecord::Base belongs_to :list has_many :list_items has_many :items, through: :list_items end class Item < ActiveRecord::Base has_many :list_items has_many :lists,through: :list_items has_many :sublists, through: :list_items end class ListItem <

问题 Hey we have three tables in our database which are connected through two relationships which are Account and Invoices. Accounts (id....) Invoices (id, sender_id, receiver_id) Relationships (id, sender_id, receiver_id) Sender and receiver are both foreign keys which reference the account table so in cakePHP an account_id. The relationship table specifies relationships where invoices can be sent or received and the invoice table displays the invoices that have been sent. How do we link both

问题 This is probably just because my knowledge with the EF Code First fluent API is lacking, but I'm stumped. I want to model the following: A Groups collection with Id and Name A Users collection with Id and Name Each user is assigned to exactly one primary group Each user may have zero or many secondary groups The table structure I'm going for would look like: Groups Id Name Users Id Name PrimaryGroupId SecondaryGroupAssignments UserId GroupId I've been beating my head against a wall trying to

问题 I have this (simplified) table structure: users - id - type (institutions or agents) institutions_profile - id - user_id - name agents_profile - id - user_id - name And I need to create a profile relationship on the Users model, but the following doesn't work: class User extends Model { public function profile() { if ($this->$type === 'agents') return $this->hasOne('AgentProfile'); else return $this->hasOne('InstitutionProfile'); } } How could I achieve something like that? 回答1: Lets take a

问题 I know, think in "denormalized way" or "nosql way". but tell me about this simple use-case. db.users db.comments some user post a comment, and i want to fetch some user data while fetching a comment. say i want to show dynamic data, like "userlevel", and static data like "username". with the static data i will never have problems, but what about the dynamic data? userlevel is in users collation, i need the denormalized data duplicated into comments to archieve read performance but also having

问题 My query is like this : <?php public function getListReviews() { $reviews = Review::where('user_id', auth()->user()->id) ->get(); return $reviews; } From the query, it can get all review data by id I want get user photo, store photo and product photo I want get it use Eloquent: Relationships How can I get it with Eloquent: Relationships? My review model is like this : <?php namespace App; use Jenssegers\Mongodb\Eloquent\Model as Eloquent; use Jenssegers\Mongodb\Eloquent\HybridRelations; class

问题 Relationship for Siblings are many to many self relationship. So, for many to many self relationship, we can define two functions in the model: public function siblings() { return $this->belongsToMany('Student', 'student_sibling', 'student_id', 'sibling_id'); } public function siblingOf() { return $this->belongsToMany('Student', 'student_sibling', 'sibling_id', 'student_id'); } The first one returns the students who are siblings of the student. The reverse is also true for siblings. So, the