Entity Relationship Diagram

Entity-relationship diagrams (ERD) are a type of data modelling which displays a graphical representation of concepts or objects within an information organisation or system and presents their relationship to one another. As the website my group and I will be create includes a database a ERD will be beneficial as we can understand all data that will need to be assigned to the database and the relationship between the different entries.

There are three main cardinal relationships, these are:

  • One-to-one (1:1): For example, in a database of employees, each employee name is associated with only one social security number.
  • One-to-many (1:M): For example, for a company with all employees working in one building, the building name is associated with many different employees, but those employees all share the same singular association with entity A.
  • Many-to-many (M:N): For example, for a company in which all of its employees work on multiple projects, each instance of an employee is associated with many instances of a project, and at the same time, each instance of a project has multiple employees associated with it.

The above information was sourced from here.

As my group have spoke of doing either a recipe site or an house finder I have created at basic ERD for a house finder website, displayed below:



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