A data model in software engineering is a graph of entity that try to represent the reality and describes how data are represented and accessed.
the real world consists of entities and relationships.
Way of modeling data:
As data modeling rules apply to all sort of domain, this section threats data modeling on a logical level and not on a implementation level.
For instance, a primary key can be represented/enforced:
A Data model graph formally define:
There is two world view:
There is not a right or wrong way of doing things as:
In a RDBMS,
In code,
See also: What are models of text in NLP? (Natural Language, Text Modeling)