Questions tagged [data-modeling]

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35
votes
7answers
11k views

Modeling first and lastname separately

Which arguments should someone consider when designing a new system and has to either store the name of a person as one field or separately as first/last name? Pros for single field: Simpler UI No ...
28
votes
4answers
6k views

Is there an industry standard for gender model other than male and female?

I am modeling a database that should be used as generic non-functional requisite for all services of the startup company, like persons, users, services and commercial data like coupons, signature ...
17
votes
4answers
46k 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 ...
13
votes
2answers
5k views

How should I design an ordered list resource in a restful service?

I've run into this same problem over and over again and I haven't found a solution that I really felt was optimal. Say in an app, you have an ordered list and you let the user change that order by ...
12
votes
6answers
2k views

How to model more than one 'last name'?

In Spanish-speaking countries we use more than one last name, like: First name ↘                           ↙ Last name   &...
9
votes
2answers
9k views

Database Design for Inventory

I am starting to design a typical product based MySQL database but I keep running in circles on how to design the tables. I have many types of products Jeans Tshirts Dresses Which have many of the ...
6
votes
3answers
271 views

Rebuilding a legacy application : What about the data model?

I am currently rebuiling from scratch a product catalogue (to feed a shopping website). The existing legacy system is heterogenous, Long story short : The some products are stored in a FileMaker ...
5
votes
2answers
10k views

How multi-valued and derived attributes are denoted in crow foot's notation of ERD?

In Chen notation multi-valued attributes are denoted by double eclipse(oval) and derived attributes are denoted by dotted eclipse(oval), but how they are denoted in crow foot notation? Also how ...
5
votes
3answers
211 views

Is an enterprise-wide data model truly feasible?

I've consulted for a number of Fortune 500 and 100 companies all of whom have made some kind of effort at creating a "Master" data model even to the point that they'd attempt to have all applications ...
5
votes
2answers
603 views

In an MVC, should models use libraries, or should libraries use models?

When I build a RESTful API, I use an MVC pattern. And in order to make controllers skinny and code reusable outside of the API (e.g. in Cron tasks), I put much of my code into services (commonly known ...
5
votes
3answers
5k views

Graph database keeping historical relationships

I'm starting the modeling of the following problem: I have many clients (millions) that interact in a network forming a graph. At the highest granularity of my business problem, each realationship ...
5
votes
1answer
4k views

Data Model for selling groups of products as one product

Say I have an e-commerce with a data model like the following, which allows a Sale to describe how a single Product is sold. This division allows a product to be sold multiple times in different ways (...
5
votes
1answer
109 views

Should an entity id contain information about entity?

If an Entity doesn't have an unique ID, we usually use auto increment number to distinguish entities. But sometimes, we have to hand that ID over to people so that they can use it. So using auto ...
4
votes
3answers
95 views

Using Multiple 'Sub-types' vs a larger single type?

I have a user model in an application that I'm working on, which currently uses sub-types to encapsulate properties depending on what type of user you are - I just can't help but think that this is ...
4
votes
3answers
172 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 ...
4
votes
1answer
976 views

Should I avoid data duplication?

I'm trying to design a relatively simple ERP system. However, there are some requirements that complicate things a little bit: It must be possible to add all sorts of contacts to the people table, ...
4
votes
0answers
522 views

What's the canonical way to store translations of user data?

I've developed some software that allows my users to attach a blurb to some non-language specific information: Pseudocode model: item(): ID creationdate byline //Only one byline for the object ...
3
votes
4answers
1k views

How would you model an objects representing different phases of an entity life cycle?

I believe the scenario is common mostly in business workflows - for example: loan management the process starts with a loan application, then there's the loan offer, the 'live' loan, and maybe also ...
3
votes
3answers
486 views

What is the normal form of JSON?

This is going to sound like a trivial question, but I like to think it's actually a deep one. The simple quesiton is, "What is the normal form of a typical JSON object?" For reference, I ...
3
votes
4answers
4k views

What is the best data model to represent mathematical range (in database, xml, json…)?

For example, greater or equal to 50 and smaller than 100 (>=50 && < 100) smaller than 10 or greater than 40 (<10 || >40) I have been thinking about how to represent ...
3
votes
5answers
570 views

In a “Revisional Data Model,” where does code that preserves a previous record's state belong?

When I say "Revisional Data Model", I mean a data model where information is never lost: Deletes never destroy any rows, and updates always cause an insert somewhere else to preserve a row's previous ...
3
votes
2answers
162 views

Is Excel data model as good as or better than Microsoft Access?

I'm working with several Excel worksheets and workbooks that need to consolidated or linked to each other. These workbooks will track client interactions for different team members. I did the initial ...
3
votes
1answer
568 views

What happens to database design process when ORM tools are used?

I have learned about database design, including normalization during my undergraduate course. When we have to model a database for a system, we can start with an ER model and then convert it to the ...
3
votes
4answers
210 views

Two user inputs that alter each other

I have a user interface with two numeric input boxes, send amount and receive amount. The values are in different currencies and are related by an exchange rate. That is, receive amount should always ...
3
votes
1answer
1k views

Handling guest users in ecommerce application

I'm currently developing an Ecommerce application and am trying to figure out how best to add a 'guest checkout' feature. The 3 main models that I am wrestling with to add this feature are Address, ...
3
votes
3answers
169 views

Should I use a physical units library for modelling domain properties if I don't need to perform computations on them?

I'm working on the data model of a service describing houses and flats. This involves storing quantitative physical properties of certain features of the premises, for example: Speed of the Internet ...
3
votes
2answers
2k views

Design patterns for processing/manipulating data

Sometimes when I write a class or piece of code that has to deal with parsing or processing of data, I have to ask myself, if there might be a better solution to the problem. Example 1: In a recent ...
3
votes
3answers
202 views

Modeling content management domain

The domain is more or less straightforward — I have an article (or rather several types of articles) that I want to edit and publish. Published article is exposed through an API to public. The thing I ...
3
votes
1answer
2k views

RESTful API/Data Modeling - How to model an subordinate resource that will only ever have one element

I'm creating an API and data model for a multi-user document-creation application and I'm having trouble with a particular part of the data model/API design. Below is my current line of thinking: ...
3
votes
2answers
195 views

How to model relational data that can be organized in multiple ways? [closed]

I’m working in a project that is building a system to manage data (10-20 million records) collected by a research organization. One of the challenges is that even though the data is superficially ...
3
votes
1answer
181 views

Algorithm/Strategy or Data structure to capture priorities sub priorities in an app

I am working on a CMS that is starting to evolve a bit. We started off with content that had the following priorities ( columnn in the db on the content table): HIGH MED LOW. Data was fetched by ...
3
votes
2answers
364 views

What's a good format for documenting hundreds of data feeds?

Several governments are starting to publish open data: datasets generated by the goverment, made freely available for citizens to use for value-added app development, analysis, and feedback. For ...
3
votes
1answer
85 views

Using an array as a member variable in a class

I have a style question for designing a class to represent a real model. Let's say I have Guide that has PointsOfInterest as a member. Would I want to do something like: class Guide { public ...
3
votes
2answers
259 views

Applying Domain Driven Design to an analysis driven domain

I am currently working on a domain that is fundamentally driven by analytics. I'll use a fictitious example to illustrate my question. Suppose the application is a service based on House Prices. The ...
3
votes
0answers
335 views

Lightweight data modeling vs traditional classes [closed]

I've heard a lot of talk about using lightweight data modeling as of late. Especially in relation to the Clojure programming language. What is it and how it differs from traditional classes regarding ...
2
votes
3answers
1k views

How to store sequential timespans in a database?

How can consecutive periods of time (defined by a start and end date) be stored in a database? For example: from 2018-01-01 00:00:00+01:00 until 2018-06-01 00:00:00+02:00 from 2018-06-01 00:00:00+02:...
2
votes
5answers
7k views

Is it Considered Good SQL practice to use GUID to link multiple tables to same Id field?

I want to link several tables to a many-to-many(m2m) table. One table would be called location and this table would always be on one side of the m2m table. But I will have a list of several tables ...
2
votes
2answers
152 views

Should ids be mapped to the implementation type

This is a question of model design, and hopefully some architecture nerds have strong opinions on this. I've been developing one that I will post in an answer. Typically, in every codebase I've ever ...
2
votes
2answers
117 views

How to represent a data model?

Often enough, the terms data model and data format are used interchangeably, but here I disagree. Let's start with the simpler one, the data format. I don't know exact definitions, but the data format ...
2
votes
1answer
820 views

Optional relationship on ERD diagram

Upon generating an entity-relationship diagram of my database I observed several occurrence like this: This diagram (in IDEF1X notation) shows the following: Our team's DB convention is that each ...
2
votes
2answers
121 views

how to model 2 objects that refer to each other in the DB

Now I have 2 objects which are "PROBLEM" and "SOLUTION", obviously "SOLUTION" is a proposed solution to a given "PROBLEM", my problem is that in my business I have the following relations: a "...
2
votes
1answer
3k views

What is an example giving the difference between Domain Model and Data Model?

I've seen many articles describing differences between Domain Model and Data Model. However none of the articles have picture representations showing difference. https://stackoverflow.com/questions/...
2
votes
1answer
162 views

many to many relationships in ER Diagramme

Relational database management systems can’t have M:M relationships, so before converting a data model to a database in Access, SQL Server, mysql, or other relational DBMS, the data modeler must solve ...
2
votes
3answers
555 views

Database design for changing user roles

What database design would you suggest for the following example? Example: Imagine a bus with some people inside. Every person has some attributes like name, etc. Also there are driver- and passenger-...
2
votes
4answers
809 views

Data Model - How to better model this circular reference

I'm designing the data model for a project where users can create documents, save revisions of that document that can be reverted to, and publish documents. The basic data model I have right now is ...
2
votes
1answer
59 views

Converting a one-to-many xml design to a many-to-many

I have an xml file format that looks something like this: <topLevelTag> <category name="foo"> <item attrib="value">ItemName</item> <item attrib="value2">...
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 ...
2
votes
2answers
453 views

Index / Unique on `deleted_at` column?

We have an Accounts table in a Postgres DB that has a unique index on user_id and product. Users can have many accounts, there's no product table. Occasionally users will create an account ...
2
votes
1answer
98 views

How to Structure Data Models as Detail or Stub in C# using Code First?

Say I have a product listing backed by a SQL table. It's a large data model (truncated here for brevity) but let's say looks like this: public class Product { public int Id { get; set; } ...
2
votes
1answer
71 views

How to model rdbms relationships as graph relationships?

I am modeling our existing database in transition to a graph database. Currently here is how I can interpret the database a graph relationships group -have-> groups group -have-> participants ...