Tag: Erd Notation

How to Change the Diagram Notation Used in Vertabelo

Learn how to change ER diagram notation in the Vertabelo database modeler. Vertabelo supports many different ER diagram notations. The default notation (and the most popular) is the Information Engineering (IE) notation, which you may know as crow’s foot notation. Vertabelo also supports UML and IDEF1X notation for logical diagrams, and UML, IDEF1X and Barker’s notation for physical diagrams. In this article, you'll see how to change your ERD notation in the Vertabelo modeler.

What a Concept! Is Logical Data Modeling Obsolete?

When databases were sized in megabytes rather than petabytes, their design was a well-defined discipline of data analysis and implementation. A progression of modeling steps – from conceptual and logical through relational and/or physical – promised successful deployment. But as we passed more orders of magnitude in data volume, we seemed to stop seeking modeling approaches to manage that volume. So the question arises: Is logical data modeling obsolete?

Crow’s Foot Notation

The most recognizable characteristic of crow’s foot notation (also known as IE notation) is that it uses graphical symbols to indicate the ‘many’ side of the relationship. The three-pronged ‘many’ symbol is also how this widely-used notation style got its name. Let’s see where crow’s foot is placed in the history of data modeling and take a look at its symbols. History: How Crow’s Foot Notation Got Started The beginning of crow’s foot notation dates back to an article by Gordon Everest (1976, Fifth Computing Conference, IEEE).

Crow’s Foot Notation in Vertabelo

Various ERD notations follow different styles for entities, relationships, and attributes. Usually there isn’t much standardization between them, so notations bear little resemblance to each other. Among the plethora of ERD diagram notations, crow’s foot notation is definitely the most used. In this article, we’ll investigate its components within the Vertabelo database model. Before we start looking into crow’s foot notation, we must understand that there are various levels of Entity-Relationship diagrams: conceptual data model – an overview of what should be included in the general database model.

UML Notation

UML is popular for its notations. We all know that UML is for visualizing, specifying, and documenting the components of software and non software systems. What’s more, UML has many types of diagrams which are divided into two categories. Some types represent structural information, others general types of behaviors. Among these, there is one that is commonly used for entity relationship diagrams. In UML, an entity is represented by a rectangle:

Arrow Notation

Arrow notation has become one of the less recognized notations in entity relationships diagrams in recent years. Let’s discuss its elements. Entity and relationships As you can see below, an entity is always represented by a rectangle, which is common to most notations (there isn’t a distinction if it is dependent or independent entity). Relationships and cardinality are represented by various combinations of arrows as the diagram below presents.

IDEF1X Notation

IDEF1X (Integration DEFinition for Information Modeling) is a method for designing relational databases with a syntax that supports constructs in developing conceptual schema. Not everyone knows that this notation has an interesting history. Indeed, the need for semantic data models was first recognized by the U.S. Air Force in the mid-1970s. As a result, the ICAM Program came into being (It identified a need for better analysis and communication techniques for people involved in improving manufacturing productivity), that later developed a series of techniques known as the IDEF; IDEF1X being one of them.

Chen Notation

Continuing our trip through different ERD notations, let’s review the Chen ERD notation. Peter Chen, who developed entity-relationship modeling and published his work in 1976, was one of the pioneers of using the entity relationship concepts in software and information system modeling and design. The Chen ERD notation is still used and is considered to present a more detailed way of representing entities and relationships. Entities An entity is represented by a rectangle which contains the entity’s name.

Barker’s Notation

When looking at different kinds of ERD notations, it is hard not to come across Barker’s ERD notation, which is commonly used to describe data for Oracle. Richard Barker and his coworkers developed this ERD notation while working at the British consulting firm CACI around 1981, and when Barker joined Oracle, his notation was adopted. Let’s take a closer look at Barker’s syntax. The most important components in the ERD diagram are:

ERD Notations in Data Modeling

An entity relationship diagram (ERD) is a diagram that defines the structure of database instances. Choosing which notation to use is typically left up to personal preference or conventions. Here, you can find some useful information about each notation: Part 1 – Barker’s Notation Part 2 – Chen Notation Part 3 – IDEF1X Notation Part 4 – Arrow Notation Part 5 – UML Notation Part 6 – Crow’s Foot Notation Which ERD notation are you using?