Questions tagged [relational-modelling]
Data structures that focus on the relationships between entities in the system, as opposed to attributes within an entity, or phases in a process, for example. Relational databases are popular application of relational modelling.
19 questions
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One and only one vs One in crow's foot notation
Am I using one and only one correctly? I have read so many articles online on differences between one and only one vs one and I'm still confused.
I.e.
a customer can exist with zero, 1 or many (...
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272
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Decoupling modules of a monolith
As part of an migration from .NET Framework to .NET Core we're looking to decouple elements of our monolith into more manageable modules. Ideally following a clean architecture/DDD/microservice ...
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Architecture for storing generic data
(I am facing this issue with code written in Swift, but would appreciate any high-level pseudocode solution, just so that I may wrap my head around the architecture)
I need to find an architecture ...
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Is there any benefit to a separate table that is one-to-one with the primary data table?
I've inherited a system with an Oracle relational database with a couple of tables modeled like I've sketched below, where there's an entire child table that only stores a single status code in a one-...
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Implementing shared content in a system with several users
I am working on a system that allows users to track their musical practice.
The system allows users to create 'exercises' that store a few pieces of information like name, description and external ...
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Designing a model for a small business which provides multiple services which generate documents [closed]
I am designing a system for a company which provides multiple services to users, all of which generate a document. The documents all have a validity period. Some of the services can be grouped, and ...
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198
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Is it normal and good practice to enlarge the amount of columns when adding new features
There is a table named is A with 40+ columns, among which around 10 are columns of hierarchical levels, in a data analysis platform maintenance and development ( legacy ) project. Due to development ...
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Modelling DropDowns in ef core
Im working on an application which essentially fills a giant government/court form.
Lets say i have an an Entity Unemployment and Unemployment has a ... thing "Reason why" and there are 6 ...
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2
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OOP: How to Manipulate Objects Using ORM Techniques?
about those objects and arraylists inside the classes, derived from one-to-many relationships, using the ORM techniques, what's the best way to deal with them at the time of setters and validation ...
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Confused over qualification association in conceptual schema UML
I am getting confused at qualification association. I perform qualification when I need to remove many-to-many relationship or when the PK of a particular table is not able to be uniquely identify a ...
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492
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Thinking about data as object vs table row [closed]
It often happens that we have a set of structured data. Let's say our data is about charitable organizations. I could turn it into a list/set of objects/structs:
struct Charity {
let name: String
...
2
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1
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118
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Best notation to store/read/compute complex relationships
I have created an application in which users and tasks can be entered.
A task should be be assigned to one or more users. If more users can do a task, the task should be assigned in such a way that it ...
- 131
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eCommerce data modeling - is it common to duplicate product properties in line items?
Suppose I have the following entities in a commerce data model:
BaseProduct (PK id, price, name)
LineItem (PK id, FK product_id, price, name)
Order (PK id, line_items)
An Order includes one or many ...
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1
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2
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142
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Class-diagram dependencies between classes
Can requirements be expressed in class-diagrams?
For example:
A student can enroll in a class.
There are different classes.
Some classes have dependencies, e.g. you can't go to Spanish III before ...
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108
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How to use strict schema with seemingly fluid data type
Our company is trying to find a good generic way to have Many-to-One data for an entity. For example, a user might have 1 primary email, but many other emails also attached to their account.
So we ...
- 277
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833
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Double way parent child relationship in Django
I am building an app to register and update children information, this information is to be provided by their tutors. Every child can have multiple tutors, and a tutor can be a tutor for multiple ...
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What are good ways to encode order between records of a relational table
For example, when an issue tracker offers the functionality to users to keep a prioritized backlog of tasks and used a relational database for persisting this information, what are effective ways to ...
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The Open/Closed Principle, how does it work for adding entities?
I'm not even sure how to ask this, but here goes:
Let's say I have a Web application that incorporates Teachers, Courses and Students in such a way that I can do things like this (pseudocode):
...
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What is the canonical pattern for database design with MongoDB?
When it comes to laying out tables in transact SQL databases, like SQL-Server and Sybase, the classic approach to relational modelling is well established. (The authority being Halpin's book)
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