Domain modeling in UML (ER model) - course RUB 11,500. from IBS Training Center, training 8 hours, Date: December 3, 2023.

Is it possible to describe the structure of a subject area in the form of text? Of course you can. But will developers be able to understand the structure of business objects and the logic of their operation after reading such text? If they can, then only in more or less simple cases.
In addition, you need to remember that the domain description is used by different stakeholders for completely different purposes. The analyst creates such a description to clearly separate those elements that are consistent with the goals of the project from those that remain outside its scope. This description helps the customer to ensure that the analyst correctly understands the specifics of the subject area and is able to offer truly useful solutions to business problems. The architect and developer draw from such a description information about the main entities of the subject area in order to implement them in the form of classes, database tables and other software objects. How can you ensure that your domain description is understandable and useful for all of these roles?

It is good practice to use visual modeling for this. Information about the structure of a domain can be well described in the form of a conceptual Entity-Relationship Model. In this case, any information or physical object available can act as an entity. in the subject area, and connections show how all these objects interact with each other friend. Thanks to this, the domain model supplements the system glossary with a visual, concise and understandable description of the “entity dictionary”.
To build an ER model, you can use various notations. In particular, this course uses UML class diagrams to build ER models. Using UML to build a domain model is especially convenient in cases where everything other project models (analytical model, design model, development model) are also built with using UML.