Linked Questions

0 votes
1 answer
148 views

Foreign Key Referencing ID of One of 2+ Other Tables

Given 3 tables — e.g. posts, comments, and tags — is there a way of having a foreign key in one of them referencing a primary key of one of the other two? CREATE TABLE IF NOT EXISTS posts ( id ...
14 votes
2 answers
24k views

Modelling a database structure for multiple user types and their contact information

I'm designing a database that will store users of varying types. Predominantly (but not exclusively) they will be Actors, Directors and Writers. Currently there are just four user types that are of ...
1 vote
2 answers
2k views

How to represent the relationship between artists and albums in an entity-relationship diagram

I'm learning and practicing with the E-R model trying to design a music industry database. With this section of the diagram I have a doubt: I suppose an album can be had by an artist and a band, not ...
17 votes
2 answers
14k views

How to model an entity type that can have different sets of attributes?

I’m having some trouble in recreating a database with a one-to-many (1:M) relationship between Users and Items. This is pretty straightforward, yes; however, each Item belongs to a certain Category (e....
16 votes
1 answer
7k views

Designing a database for a video game business domain with multiple many-to-many relationships

I am relatively new to database design, and I decided to make my own hypothetical database for practice. However, I am having trouble modeling and normalizing it, as I esteem that there are numerous ...
9 votes
2 answers
6k views

Developing a database for a funds transfers business where (a) people and organizations can (b) send and receive money

In the business context of relevance, both members and organizations need to have an account for funds. Funds can be transferred from member to member, from member to organization, from organization ...
1 vote
0 answers
691 views

Modelling an entity-relationship diagram for a scenario involving companies, services, and clients

I am creating an entity-relationship diagram (ERD) for managing workflow and other details of Company X in which I am maintaining details of the following objects: Employees of Company X Services ...
11 votes
2 answers
3k views

Conceptual ERD Multi-table many to many, or possibly recursive?

I'm creating a conceptual diagram [yes, I know I've included attributes and keys - but this is just for me to consolidate what I'm doing whilst learning] -- so please treat it as Conceptual with the ...
1 vote
0 answers
439 views

How to create entity-relationship diagram for tables that can potentially be united by an "IS A" relationship?

I have this schema: create table hall( building-id int, hall-id int, capacity int, primary key(building-id, hall-id) ); create table semester( sem-id char(5), start-date date, eend-...
8 votes
1 answer
3k views

Database schema for entities with two possible owner/parent types?

I'm using PostgreSQL with Sequelize as my ORM. I have one type, User. The second type is Group, which can have any number of users associated with it through a GroupMemberships table. Users can also ...
1 vote
0 answers
95 views

Designing a database for the academic activities of individuals or departments

I have a database which stores the academic activities in which some individuals or departments are involved. An activity could be any among some of these types: article (written) course (imparted) ...
2 votes
2 answers
276 views

Designing a scenario where a primary key could be of two types

I have a table: all_info, where it holds the users identification. The id of this table can be of two types (just one or another, never both), suppose: int and varchar, but one table can't have two ...
1 vote
1 answer
101 views

How to make Event (like a Party) Sources mutually exclusive?

I'm designing an entity-relationship diagram (ERD) for a marketplace of events. An event can be created by a user, in which case the Event table must have owner_id or we pull it from an API in which ...
9 votes
2 answers
2k views

Advice on a basic design, first time database design

I am taking a course to become a Java developer. The course involves using databases but we never really design any, unfortunately. Most of the time we get pre-made databases and we have to ...
7 votes
1 answer
2k views

How to model a Letter Transportation business context in a database diagram?

I am trying to crate entity-relationship diagram for a transport company database. This database should store information about letters, deliveries, moving letters from one warehouse to another, and ...

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