Class, Attributes and Methods - All Concepts Explained

In the next video, you will see how to represent a class, its attributes and methods in a UML diagram.

The syntax for drawing a class is as follows:

Order class:

Some conventions to follow while drawing classes are as follows:

• The class name is written using the Upper Camel Case convention. This means that a class name starts with a capital letter. If there are multiple words in the class name, then they should be joined together without spaces in between, and each word will start with a capital letter.
• Attributes are written using the Lower Camel Case convention. This means that an attribute name starts with a small letter. If there are multiple words in it, they would be joined together without spaces in between, and each word will start with a capital letter.
• Method names and parameters are also written using Lower Camel Case.
• You need not show all the attributes and methods for a class in the class diagram; if you do, your class diagram will be too messy to comprehend.

Video Transcript

We will now see how to represent a class in a UML, a class diagram is represented as a rectangle with multiple compartments inside. The first compartment at the top shows the class name followed by the next compartment at below shows each of the attributes within the class. Below that, the last compartment at the bottom shows all the methods inside the class. Let's now take an example of a class and show how it will be represented. For example, if we take an order class, the order becomes the class name which is represented at the top. Let's say this order has an attribute called order ID. The order ID, which could be an integer, becomes an attribute or the property of the order class which could differ from each order. In this case, the order ID is generic as we said in the blueprint based on each order for each object, the order ID will change. The next would be the methods of that order class. For example, we could check the status of the order or the order name. So all these methods

corresponding to that order class is represented in the third rectangle at the bottom. So if you can see to summarize, a class diagram largely has three major compartments the top one, the class name the middle one with all the attributes or the properties along with their data types which could be like integer or String. And then lastly finally the method which showcases the method names along with the arguments or the properties of that methods along with the data type of those attributes arguments. 

Video Recap

• A class diagram in UML represents a class as a rectangle with three compartments.

• The top compartment shows the class name, the middle compartment shows the attributes or properties of the class, and the bottom compartment shows the methods of the class.

• An example of a class is given, such as an order class with an attribute of order ID.

• Methods for the order class, such as checking the status or name of the order, are represented in the bottom compartment.

• In summary, a class diagram has three compartments for the class name, attributes, and methods. Attributes include data types like integer or string, and methods include arguments or properties with their data types.