Entity Relationship Diagram

Week 1 Discussion

Lionel Sharpe

Professor Hector Molina

Sanford Brown College Online

The main points to consider when creating an ERD (Entity Relationship Diagram)

An ERD is known as a graphical representation from a system of information that will show a relationship between concepts, people, places, objects, and events that are held within the system they are creating it from. The ERD is known to be a technique on Data Modeling, and helps to define processes in a business that are mainly used as a foundation for a database that is relational to this information. The ERD is good for keeping data organized, so that it will be shown in a relational structure, that will represent unstructured data and semi structured data.

There are three main points to focus on when creating an ERD for anything and they are as follows.

The entities – objects and concepts, that store data on them

Relationship between the entities

Cardinality – the relationship in the numbered term.

Cardinality would refer to the attributes, and the relationships the entities have with each other. Here is the cardinality that is used to represent the entities in a database.

1 to 1 – people in the database associated with one item.

1 to M – One too many, a single item may be associated with multiple customers.

Many to Many- company may have multiple customers, and the customers will have multiple agents in the business this is a many to many relationship.

Last the database has three levels of abstraction and they are as follows:

Conceptual level, this is the logical structure of the whole database, along with the information and relationships between the data that is in the database.

External, the views of the database depend on the user.

Internal Level, this is the physical storage details of the database within the computer that is used.

Works Cited

"What Is Entity Relationship Diagram? - Definition from WhatIs.com." SearchCRM. Web. 08 Feb. 2016. .

MLA formatting by BibMe.org.

Created on March 13, 2016 by Lionel Sharpe (student) || Professor Hector Molina at Feb 08, 2016 03:41 PM

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