Questions tagged [relationships]
The relationships tag has no usage guidance.
57
questions
1
vote
2answers
66 views
Relationship between entities in different aggregates and size of aggregate
I read a lot about DDD but few thing are still unclear. At this moment I have two dilemma
The size of aggregates. How small could be an aggregate?
For example we have:
class Car {
String colorId
...
0
votes
1answer
92 views
What kind of Relations should I have in my E/R Diagram
I am trying to create an Entity/Relationship Chen Diagram for a new APP. Scope is simple enough.
I will have multiples types of users login through the same Login Form.
What I decided to do... Is ...
1
vote
1answer
248 views
UML Use Case Diagrams Relationship - Required / Optional AND independent
I am learning to create Use Case diagrams using the UML specification, but I have a couple of doubts about Use Case relationships which I cannot solve on my own.
My question regards two different ...
4
votes
1answer
911 views
Designing a REST API resource with a non-unique ID, but unique composite ID
Is it bad for a REST API to have non-unique ID for a child resource?
For example, the endpoint is:
GET /parent/:parent_name/child/:child_name
The :parent_name is unique, but a :child_name is only ...
3
votes
2answers
2k views
What is the difference between containment and aggregation relationship in UML?
As it is said in ARLOW, J., AND NEUSTADT, I. UML 2 and the Unified Process, 2nd ed book, there are 7 types of relationship between different objects.
Dependency
Association
Aggregation
Composition
...
1
vote
1answer
210 views
How to show relationships of the component containing the interface definition when using ball/socket notation in a UML Component Diagram?
I recently found out that I have probably been using ball/socket notation in a wrong way all the time. Now I am confused by the different ways of drawing interface relationships in two regards (I ...
3
votes
6answers
391 views
UML aggregation: how can the “whole” exist without its “parts”?
I understand aggregation is a "whole/part" relationship, where the "parent" class is the whole and the "child" class is the part (and this is unidirectional), and that each class exist independently (...
1
vote
1answer
27 views
Approach to modeling for a new attribute to attach to exactly one of the many in a one to many relationship
Apologies for the awkward title; I wasn't quite sure how to concisely describe what I'm trying to do. My situation goes like this:
We have a Product table in our database;
Each Product may have 0 or ...
0
votes
3answers
2k views
Many to many relations in Domain Driven Design
I am new at domain driven design, and want to learn some about aggregates. For example I have a User and Role entities.
public class User {
public string Id {get; set;}
public string Username ...
18
votes
11answers
10k views
Need Good OOP Design For World and Countries Problem
I am currently working on problem with a chicken or egg first situation.
Basically, I am designing a solution which goes like this:
World is a collection of countries;
Each Country has a name, flag ...
2
votes
1answer
145 views
Can we have a ternary relationship together with a recursive one in E-R diagrams
I am designing an E-R Diagram for a simple system where there are some users and contests. A user can create a contest or invite other users to the contest who can decide to accept or not.
I am ...
1
vote
2answers
94 views
How to show UML component load/discovery and realization relationships
In a UML component diagram I want to show two components (among others). One is the core component that loads contents (classes) from the other. It's much like a testframework loading unit tests/test ...
2
votes
3answers
129 views
Many-to-many assignments in user system
I have a few software architecture/design questions related to a technically quite simple problem. We already have all the functionality implemented properly, however from a design perspective it is ...
-1
votes
2answers
1k views
How to handle many-to-many relationships with multiple incompatible relationship types in RESTful API?
Note this question is about when there are multiple relationship types. This is not the same as this question, where there is only a single member relationship.
Say we have persons and organizations. ...
asked May 29 '19 at 14:35
André Christoffer Andersen
1,0071 gold badge9 silver badges14 bronze badges
4
votes
3answers
170 views
ER diagram - feasibility of a requirement
I need to model the following requirement in an Entity-Relationship diagram.
"Customers place orders, which contain a list of products with their quantity and prices. A shipment is made when ...
1
vote
3answers
122 views
Database relation design
When I develop apps I reach situations like this frequently but I never found a best practice to solve it.
Imagine:
We have chats, each chat can have many message.
We have tickets, each ticket can ...
3
votes
1answer
124 views
Proper way to associate data to users that are stored in external database?
I have this IdentityServer which handles authentication and authorization. It saves users, roles, claims, etc in its own database.
Then, I have a web app that needs to protect some resources to ...
4
votes
3answers
1k views
Factory pattern or builder pattern ? which one is suited for reading Finite Element Model data from a text file?
A follow up to another question (Making a design decision about reading model data from an input file).
I wish to ask another question regarding builder or factory pattern. (I read that builder is ...
1
vote
1answer
1k views
Entities and polymorphic relationships
Lets say that I have a shelf on which I can put items that are shelfable (not sure if that is actually a word but you can understand my point).
So I have the following:
class Shelf
{
/** @var ...
4
votes
2answers
164 views
How to represent relations between multiple objects without obvious aggregate root
Let's say we have three types of objects:
Agents
Calls
CallsQueues
They all can be linked with each other (1to1, 1toM, MtoM) or have no links, and these links change over time. Calls wait in ...
3
votes
1answer
800 views
How to organize business logic which deals with different, but related objects
The task
The piece of software I'm writing operates on the following object types:
Agents
Calls
CallQueues
These objects can be linked together, and each of them contains some additional ...
4
votes
2answers
1k views
Best diagram to show relations between several applications
I'm currently an intern at a company. For my intermediate report I Received some feedback about displaying the relations between multiple applications.
So in my image all 3D rectangles are a deployed ...
0
votes
0answers
641 views
Examples for bidirectional and unidirectional relationships between objects
To better demonstrate the difficulties of reading/updating objects in a multithreaded environment, I'm looking for examples for groups of objects with a bidirectional or unidirectional relationship ...
1
vote
1answer
499 views
Imposing conditional entity relations
While working on an application, I am facing an issue. And I am not sure how to solve this.
For explanation I have managed to come up with a simple example below:
Consider a Grocery Store ...
2
votes
1answer
123 views
Looking for a strategy to ensure name of child node stays unique in collection
Even though I'm programming in PHP, I'm open to reviewing language-agnostic suggestions, as they might point me to valuable directions.
To remove any possible confusion I feel some comments appear to ...
3
votes
3answers
232 views
How can I mark one of a 1:n relation as the “default”?
I have an "easy" question, but since I am not a very experienced programmer I would like to hear what some of you have to say.
If I have for example a Db called MyDb with many tables. Two of them are ...
0
votes
1answer
201 views
What are best practices to maintain a list in the database in Rails?
I have list boxes and model relationships in the database. I'm doing the following migrations to maintain lists, rename items, and add items:
def up
Fund.create min: 0, max: 1_000_000
...
2
votes
3answers
999 views
UML : is it okay to use only Association in a class diagram ?
I feel confused about the three relationships Association, Aggregation and Composition in UML. I need to finish a project soon, until it became less unclear in my head, is it okay to use only ...
14
votes
4answers
43k views
ERD: “many” vs “zero or many”/“one or many” crowfoot notation?
Background
I saw this figure describing the different crowfoot notations used in ERD:
I'm not able to find the difference between the "many" notation and the "zero or many. However I was able to find ...
1
vote
1answer
150 views
Can the has-a relation in OOP become ambiguous or difficult to know?
Assume I have the following code.
class D { static Integer i1 = 42; }
Is it true that D has an Integer? Or is it only for instance variable that we can have a has-a relation?
I also wonder about ...
3
votes
4answers
239 views
Hierarchical structure that needs to enforce availability
The project I am working on has deep parent/child relationships that needs to enforce availability.
Imagine we are a large Worldwide Electronic Seller (Best Buy) and selling mobile phones
We have ...
5
votes
2answers
1k views
Specifying a bi-directional unique constraint on a join table in Postgres [closed]
Problem description
I have a situation where I want to enforce that a relationship can only be defined once and I want to solve it on database (Postgres) level.
The following situation I consider ...
4
votes
2answers
177 views
Designing my classes with relationships
I need to build a UI for entering values to the database. I am stuck with my class design to achieve it.
I need a UI where I am able to enter the name of the system. Each system can have many options....
0
votes
0answers
63 views
How to model relationships in scenario where every product can (don't have to) be associated to only one category
This one still occupies my mind. How do you model 1:N relationships.
Consider having a category and product (typical e-commerce scenario).
Every product can (don't have to) be associated to only one ...
0
votes
1answer
2k views
Database design for linking parent & child relationship
Currently i have requirement saying user from an UI creates there own forms which has types textbox,choicegroup etc..
Does anyone have a any idea on how to architect the database to store all data?
...
1
vote
1answer
1k views
Laravel relationships and database schema
I am playing around with Laravel and came across something in the documentation for defining 1 to 1 relationships between tables that I would like to get feedback on.
The example in the docs is ...
2
votes
2answers
1k views
Is composition and aggregation really a type of association relationship?
From Wikipedia:
There are four different types of association: bi-directional,
uni-directional, Aggregation (includes Composition aggregation) and
Reflexive.
From what I know:
Composition ...
1
vote
1answer
93 views
How to associate both a collection and one item of this collection to an entity
I'm working on a project in which I have an entity, we may call Users and another entity Address.
I want to define the entity User in a way that an user would have a collection of addresses (...
1
vote
4answers
363 views
Domain model associations that do not required the behaviour of the associated object. How to model?
I've been struggling with this question for a while.
I'm specifically thinking within the object orientated domain model.
Let's say I have two entities. A supplier and a customer. There is a ...
1
vote
3answers
347 views
Pattern to safely establish a one to one bidirectional relationship
Let suppose we have 2 classes, Pilot and Plane, being in an optional one-to-one relationship. So a Plane might have a pilot when it's flying, but when it's standing in its hangar, it has none. Similar ...
8
votes
1answer
616 views
Relation between objects
For a few weeks I’ve been thinking about relation between objects – not especially OOP’s objects. For instance in C++, we’re used to representing that by layering pointers or container of pointers in ...
2
votes
3answers
1k views
Should POCO domain classes contain collections?
The question title is not good, but I couldn't think of a way to word it better.
I am used to develop using POCO classes in my projects, that is, domain objects contain absolutely no logic, only data....
3
votes
2answers
1k views
MVC: “User” model gets big and crowded. Should methods that do CRUD operations on one-to-many relationship data be in different models?
In most MVC web projects there is a User class. Many times a user has something else in a one-to-many relationship, i.e. orders.
If we have a user class that has many orders, should methods that add, ...
1
vote
1answer
452 views
Need help modelling a User/Project/Task relationship
So I'm creating a very simple project/task management application in Laravel 4 and I'm not sure how these relationships would work. I have a Project, Task and User model. A User can own a Project or ...
2
votes
1answer
1k views
REST Relationships Besides Parent/Child
This would seem to be a pretty basic question, but I can't seem to find appropraite guidelines for it. What is the "restful" way of POSTing a relationship between two entities that are not necessarily ...
11
votes
2answers
16k views
Database Schema for Pricing Products (packages, promotions, qty based, limited time offer…)
I'm working on a new point of sale for a company that products for different prices depending on the product mix.
All products have a base price.
To explain my problem, I will use the following info:...
4
votes
1answer
469 views
Database Design - Optimise Relationships
I am about to embark on a redesign of an application, one where querying the database is particularly annoying. I intend to redesign the database as much as possible but the data shape cannot change ...
0
votes
1answer
145 views
Keyword Collection, ManyToOne or OneToMany relationship?
I hope this is the right place for this type of problem.
An Object of my class Movie can have several keywords ( like 'fight club', 'brad', 'fincher'), and be part of different categories (like '...
4
votes
1answer
383 views
What is the name of this relationship between objects? [closed]
Different types of dependencies have particular names, such as linear dependency, circular dependency, self-referencing object, etc.
What is the name of the dependency where those rules are true?
A ...
2
votes
3answers
23k views
Relationship DAO, Servlet, JSP and POJO
I want to implement a JSP, POJO, DAO and Servlet in my J2EE program. However, I don't fully understand how the relationship between these elements should be. Is the following (MVC) setup the right way ...
