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Data Modeling

Data modeling is a technique to document a software system using diagrams and symbols. It is used to represent communication of data. The highest level of abstraction for the data model is called the Entity Relationship Diagram (ERD). It is a graphical representation of data requirements for a database.

Entities can be thought of as nouns. Examples: an arrist, a computer, an employee, a song, a mathematical theorem, etc.

Two related entities

A relationship captures how entities are related to one another. Relationships can be thought of as verbs, linking two or more nouns. Examples: an owns relationship between a company and a computer, a supervises relationship between an employee and a department, a performs relationship between an artist and a song, a proves relationship between a mathematician and a conjecture, etc.

An entity with an attribute

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Entity Relationship Diagram

The main value of carefully constructing an ERD is that it can readily be converted into a database structure.

There are three components in ERD.

  • Entities: Number of tables you need for your database.
  • Attributes: Information such as property, facts you need to describe each table.
  • Relationships: How tables are linked together.