Questions tagged [relational-database]

A relational database is a digital database based on the relational model of data. This model organizes data into one or more tables (or "relations") of columns and rows

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Specifying a bi-directional unique constraint on a join table in Postgres

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 ...
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1answer
705 views

Design for syncing data from remote API

I am trying to find a robust and correct solution for syncing data from different sources to my local relational database. I have different sources of data for eg: CSV, REST API and probably network ...
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0answers
541 views

Building a generalized notification system: passive vs. active

Recently, I've tried my hand at building a notification system, but I quickly found that notifications are tricky things, especially in the context of building a general model. The diversity of what ...
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0answers
532 views

Is this a good implementation of mongodb for a money management tool?

I have a money management tool which has users. Each user may have several accounts/funds (e.g. bank account). For each account/fund there may be thousands of transactions. Users may only view their ...
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0answers
656 views

Redmine - Database Structure/Normalization

I am using redmine for project management and issue tracking. I was looking at the database tables and the underlying structure and was wondering if anyone who is experienced with database ...
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0answers
25 views

DataBase design generated by hibernate Many to Many for MariaDB

Hi I am in middle of designing DB and Got a little bit confused about DB Design. I am Using Hibernate as ORM Tool ahd mapping between Page and Step entity in hibernate. @ManyToMany(fetch = FetchType....
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2answers
96 views

Reporting with cyclic or relationships

I’ve got me a design and implementation problem extracting and formulating the results I need. What I’m trying to do is build some reporting on forecasted stock commitments in an inventory system to ...
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0answers
167 views

How to maintain table relationship across services in with a micro-service architecture

I have a scraper service that looks for media online. For every source type, there are two tables. A common source table and a source_type_media table that are related by source.id to ...
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0answers
36 views

Database Constraint from another table column

Let's consider the following objects : Article which can be of different types Equipment which point to an Article, some fields on equipment are only used for some types. I want to add constraint ...
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1answer
203 views

Best way to model pricelist per customer for products in webshop

I am making a b2b-webshop system that will have multiple customers. Each customer will have a separate active pricelist which contains the products that they can buy and the prices that applies for ...
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0answers
32 views

Design a way for multiple and single group mapped to a Role?

Currently I am trying to setup a relationship between user groups and roles. I am trying to satisfy: Multiple roles apply to single group multiple groups can have same role multiple ...
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0answers
33 views

ACL entity and microservices database relations

I would like to build a microservices architecture to handle the following scenario: I have a building. The building has some kinds of devices. And the devices can be used by the users. In the system, ...
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0answers
53 views

Designing database relationships for a voting application

So I designed database relationships for a voting/polling application. I want a user to only be able to pick 1 option on a poll. I want multiple options per poll. So what I have here is this. User ...
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0answers
575 views

Use of UUIDs (Primary key) in a REST API

I faced the problem bellow when I designed our new app. We are thinking to have one extra column for some tables which is a UUID for security purposes. So, there are two different solutions. First ...
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1answer
105 views

How is called the reciprocal operation of the join on two tables

Consider two tables in a relational database 1|A 2|B 1|X 1|Y 2|Z whose join on the first column is (if we drop the column used for the join) A|X A|Y B|Z How is called the converse operation ...
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1answer
53 views

Databse model: Entity that can have values from two different tables or user input values

I'm modeling a database, where I have a table called "appointments" (citas in spanish, but I would translate the tables's names for better understanding) where the user can create an appointment to ...
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3answers
116 views

DB architecture for managing items of different categories

I'm making a rental app which has many categories with unique properties Example: Category 1 Car which has Fuel, model, color, speed Category 2 Apartment which has Rooms, lift, ...
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1answer
105 views

Relational Model to NoSQL model

I'm trying to switch my brain in to a NoSQL mode (document oriented database). I created a JSON datastructure that looks a little bit like this { "listInstances" : [ { "listClassId" : 1, ...
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2answers
203 views

Hierarchy in ER and OO Model

So, it might be a very fundamental question, but I'm pretty confusing right now... It's all about Element and ElementCategory: an element belongs to a category, a categoty can have many elements - a ...
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1answer
45 views

Preuso/empty entity or only real entities + nulls?

I have a table "products" and a child one "product_modifications" Some products have "product_modifications": "colour", "size",, .... But not all. When a client orders a product, views pictures and ...