What is ERD????

in #teammalaysia7 years ago

Hey guys in my previous post I show the tutorial on how to make an ERD.But now I am gonna go a little bit deeper in this topic.

First of all my question is what is ERD.Well you can say that it is a short form for Entity Relationship Diagram.Well it is basically just a diagram to arrange your data properly in order to make it easier to understand.ERD is more like a preparation before you create any system.

simple-chen-erd.png

But what is Entity?
Entity is an object or concept that is unique and can be recognised in your daily life such as

students, teachers, books or examination

stock-vector-cartoon-teacher-and-students-305000852.jpg
books-clipart.jpg
scantron-and-pencil.jpg

Well that just an example if you want to create a system based on school.

There are also two types of Entity which is strong entity and weak entity.

Strong-entity-and-weak-entity.jpg

As you guys see on the picture above strong entity can exist without the existence of other entity.on the other side weak entity can only exist if there is a strong entity.Weak entity is more like a support while the strong entity is the main important thing in ERD.

Thank you very much guys.On my next post I will tell you guys about attributes in ERD.And again I am sorry if they are any grammar mistake in my post.