Entity Relationship Diagrams explained by Sonic the Hedgehog

Hi Helen, that's a nice post! I've clicked through this post because of Sonic but left with some newfound knowledge. 😁

I just want to check if I got what I'm reading right...

In short, some uses of Entity Relationship Diagrams(ERD) are:

1. visualization of relationships between data
2. serve as plans for implementing the database
3. communicating these plans
4. determine requirements
5. debug system

And those uses translate naturally into "Why we use ERD".

While I can clearly see how ERD is used to serve the first 3 purposes, I have no more than a vague idea on using them for 4 and 5. If possible, do you mind elaborating on using ERD to determine requirements (and what sort of requirements) as well as using them to debug systems.

Thank you so much for this wonderful post! I will probably be reading through the rest of the BI series as well 😄

P.S. I have another question that's not really related to the content of the article. The part where you add the 5 circles to show the article being part of the "Business Intelligence Series" is so cool! I just wanted to know what is it called so I can also add it to my own posts.

I love what you describe and your words. The following is a code demo by js:

// Conceptual Data Model
const EntityRelationshipDiagrams = {
  Zones: class {
    // Logical Data Model
    constructor() {
      this.ZoneId = EntityRelationshipDiagrams.PhysicalDataModel.getId(105);
      this.voice = "truths";
    }
    // Physical Data Model
    speak() {
      return `${this.ZoneId} ${this.voice} as work`;
    }
  },
  Boss: class {
    // Logical Data Model
    constructor() {
      this.BossId = EntityRelationshipDiagrams.PhysicalDataModel.getId(0);
      this.voice = "barks";
    }
    // Physical Data Model
    speak() {
      return `${this.BossId} ${this.voice} in the meeting`;
    }
  },
  // external Physical Data Model
  PhysicalDataModel: {
    getId(num) {
      return num < 100
        ? this.getRandomInt(0, 100)
        : this.getRandomInt(num, 1000);
    },
    getRandomInt(min, max) {
      min = Math.ceil(min);
      max = Math.floor(max);
      return Math.floor(Math.random() * (max - min + 1)) + min;
    }
  }
};

Nice article!

Just noticed that the entity 'Zones' has an attribute 'ActID', which shouldn't be there if I am correct. A one-to-many relationship should only have a foreign key on the 'many'-side, as having one on the other side does not make sense. Having 'BossID' there would make more sense ;-).

Nice post!!!
I think you can try dbdesigner.id to create Entity Relationship Diagram 😎😎😎.
This can help you to collaborate with your team on web and cut off your step in generate SQL Create database.
I write this article to explain more about this devtool dev.to/didin1453fatih/database-des...

Gotta go fast! Great explanation!

Hi. Wich is the diference between "one" and "one and only one". When i started in this world, 2002, one meaning "only one". No put two marks min and max because the value was the same, to min to max. I can see lucidchart and a lot of people, now use 2 marks, but then, i dont understand if 2 diferent values or the same value but diferent notation. Thanks for your help.