I started working in a start-up for a week now and I've been assigned the database side. I have no prior experience with databases and I'm studying as much as possible about them. We're using Airtable as our relational database. A week in, after some studying I realized that they think they're using Airtable as a database, but it's just basically a spreadsheet, because it doesn't respect any of the relational databases rules (no primary keys, data duplication without correct linking of records ecc.). But while trying to lay down an ER diagram for what will be our real database I got stuck, because CARDINALITY is confusing me.
- We should have a marketing team that attracts customer and to keep track of how many customers each marketing person attracts.
- Each customer will be offered three services: Share his books, Rent and read a book or request a book in case we don't have it in our database.
This is only part of all of it, but understanding this little part will probably help me grow this diagram.
This is the ER Diagram I've came up with at the moment.
Please consider the following:
This model will morph and change as you better understand the reality and what is not communicated to you while you put the puzzle together.
Good luck.