Understand the Conceptual Data Model
After drawing the action flow in your activity diagram, it’s now time to look at another key aspect of your system: the data. To do this, we’re going to create a diagram called a conceptual data model.
A conceptual data model (CDM) is a tool used when designing databases to provide a structured, visual representation of the data and its relationships within a system or project.
A CDM is very useful for helping developers to configure a database and provides them with a precise understanding of how it needs to be structured.
It gives you an overview of the data and helps you understand how it is managed and linked together. It’s a very important tool for planning, developing, and maintaining an application.
Identify the Main Elements of a CDM
When creating a CDM, it’s essential to know its key components. These are primarily entities, attributes, and relationships. Let’s explore these elements so that we can better understand their role in the CDM structure.
Data entities
These are the different types of information that you’re going to store. For example, in a rocket design application, you might have data on different types of rockets, components used, planned missions, astronauts, etc.Entity characteristics (attributes)
For each data entity, you’ll need to define its attributes. For example, a type of rocket might have a name, payload capacity, height, etc.Entity relationships
You’ll need to identify how the different data entities are linked to each other. For example, a rocket is linked to several components, a mission can use a certain type of rocket, an astronaut can be assigned to a particular mission, etc.
Here’s a demo of a conceptual data model being created:
Over to You!
Background
You’re a project manager at AirGalaxy—a company that specializes in launching rockets. You’re working on a new application that controls and manages rocket launches.
Instructions
In the current application architecture, you've noticed that there are no user profiles defined. Your task is to create a conceptual data model (CDM) to represent this “User” entity and its relationships with another entity, “Rocket Launch.” You’re going to use the online tool Whimsical to create the diagram.
Draw the entities:
Using some modeling software (or even a piece of paper), draw two rectangles. Label the first one “User” and the second “Rocket Launch.”Identify and add attributes:
Within the “User” rectangle, add relevant attributes. For example: “User_ID,” “Name,” “Email Address,” etc.Within the “Rocket Launch” rectangle, add attributes such as “Launch_ID,” “Date,” “Rocket type,” etc.
Define and draw the relationships:
Draw a line between the two rectangles to represent the relationship between “User” and “Rocket Launch.”Next to this line, specify the type of relationship. For example, if a user can launch multiple rockets, but one rocket can only be launched by a single user, the relation would be “1:N” (one to many). Label the line “launches” to indicate the user action on the rocket launch.
Let’s Recap
A conceptual data model is a tool that shows a visual representation of some data and how it is linked together for the purposes of a project.
It helps to visualize and structure the data and is essential when developing an application.
It consists of entities (information), attributes (details), and relationships (links between the pieces of information).
Now that your specifications are clearly represented as diagrams, it’s time to start devising your test strategy. The verification and validation plan will help you structure your testing and guarantee that the functionality will be developed in a robust way.
