Linked Questions

12
votes
3answers
5k views

Modeling a scenario in which each Music Artist is either a Group or a Solo Performer

I have to design an entity-relationship diagram (ERD) for a business context that involves the delineation of music artists, as I will detail below. Scenario description An Artist has a Name, and ...
16
votes
2answers
13k views

Many to Many and Weak Entities

I have an entity that cannot exist without being defined by another, and I want this entity to participate in a many-to-many relationship. Example: An artist has an album (the album cannot exist ...
11
votes
2answers
5k 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 (...
9
votes
1answer
3k views

Designing a friendships database structure: Should I use a multivalued column?

Say I have a table called User_FriendList, which has the following characteristics: CREATE TABLE User_FriendList ( ID ..., User_ID..., FriendList_IDs..., CONSTRAINT User_Friendlist_PK ...
9
votes
2answers
4k 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 ...
7
votes
2answers
1k 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 ...
4
votes
1answer
5k views

When to use unique composite keys? [closed]

When creating a database structure, I tend to create unique composite keys for every group of data that needs to be unique. Beside them I usually use a primary key (usually INT AI id), unless a ...
11
votes
2answers
1k views

Best data modelling approach to handle redundant foreign keys in a database about Surveys, Questions and Responses

I am looking for advice on the best relational modelling approach to store surveys, questions, and responses. I am looking for which of the two approaches below looks best, or an alternative approach ...
2
votes
1answer
2k views

How to remove data redundancy in product table if multiple suppliers are there for same product

I am designing a database where I have different products and suppliers. For example, I have a product, "mobile phone", say an Apple 5S. This will be sold through my website from different suppliers ...
6
votes
1answer
615 views

Entity-relationship diagrams and application program functionalities

It seems that the core functionalities of an application program I'm working on are nothing but associative entities. Hence one-to-many relations sort of produce "metadata" that will only feed (one ...