Logical Data Modeling
About
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:
- similar things are called entity
- with relationship
- that can be organized by a nominal attribute:
- associated
- hierarchy
- …
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:
- in a relational database by a primary key constraint
- and in code by a map
A Data model graph formally define:
- data entity (node, vertice, table)
- and relationships among them (egde)
There is two world view:
- and an event-oriented
There is not a right or wrong way of doing things as:
- design decision involves trade-offs between:
- against reduction of data duplicate and design complexity.
- every data model is meant to evolve. See Gay marriage: the database engineering perspective
Articles Related
Functionality
Domain
Relation Database
In a RDBMS,
- a table represents a data entity
- and the foreign keys, the relationship
Code
In code,
- and the relationship can be:
- structural (external variables) - ie data based
- or functional (dependency) - ie function based
Text
See also: What are models of text in NLP? (Natural Language, Text Modeling)