Entity Relationship Diagram (ERD) Tutorial - Part 2

Learn how to create an Entity Relationship Diagram with Primary Keys, Foreign Keys, and Composite Keys in this advanced ERD tutorial. We provide step-by-step training on how to identify these different keys, as well as helpful information on bridge tables, data types, and how your ER Diagram relates to a database management system.

A Primary Key is an attribute (or field) that uniquely identifies every record in a certain table. There’s one Primary Key per entity, and they must be unique, never-changing, and never-null. You note a Primary Key in your Entity Relationship Diagram with “PK” to the left of the appropriate attribute.

A Foreign Key is an attribute in one entity that links to the Primary Key of another entity. Consequently, they enable relationships between those entities. There can be multiple foreign keys per entity, or none at all. You note a Foreign Key in your ERD with “FK” to the left of the appropriate attributes.

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00:00 Overview
0:32 Recap from ERD Part 1
00:51 Primary Keys
00:56 Primary Key Examples
1:54 Primary Key Rules
5:43 Lucidchart
6:06 Foreign Keys
7:43 Foreign Key Rules
8:20 Composite Primary Keys
10:11 Composite Primary Key Rules
10:46 Bridge Tables
12:50 I've finished my ERD. Now what?
14:19 Wrap Up

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Follow us:

[muriyadanthomson]

Best explanation of ERDs on the internet! Thank you! 🙌

[rishitratan]

The CSV to ER diagram functionality in Lucid Chart is huge! Such a simple yet useful idea.

[drchid]

The fact it can convert the diagram to code to create the tables! And to be able to do it in reverse from database to diagram! That is awesome and such a big time saver🙏🏾 thank you 😊

[timhendriks]

insanely good video, even helped me for my data mining course just to revisit the basics

[simhthmss]

Please make more "lucid explains the internet" videos. Such as the snek and doggo videos. These are still being shared around social media to this day.

[diderdubois]

I've worked on thousands of databases, yet I watched both parts with laser focus. The quality of this content is simply incredible. I wish I had access to that when I started out.

[benaya]

a great explanation, as always. one thing is missing for me - the relationship between entities(other than the quantitative you mentioned), and dependant entities and their notation. thanks alot!

[hassanaliomurdad]

You got a new subscriber with this video. Kudos to you!

[lovetheentertainment]

Make a full course It will be easy to follow in a structured way

[DeKiesel]

THANK YOU SO MUCH!
I always used the export button in the right panel (it is much more prominent) and I found it so annoying to have to export all tables one by one.

[safiharisna]

Thank you for your explanation! how about alternate key and candidate key??

[Ethan_]

If you do any requests/suggestions: may I suggest more sneke videos?

[cryptoWorldever]

what a great piece of software it is. thanks very much sir

[SunshineBurrito]

We need more charts!!! We miss the charts :(

[enockrotich]

this is really helpful. Keep up the good work

[mkn]

I like this guy. He explains everything really well and he is a big dude named Bear. As a fellow big dude i appreciate his name lol.

[dcatmakas]

thank you a lot for this perfect video..

[biomagician]

Hello, and thank you for the great video! Where should I store the meaning of each column? Is it possible to add a 4th column to each table in a second toggable layer? Or should I store the column meanings in a different document in Lucidchart? Or in a different software altogether? Thanks for your insight!

[waadturki]

We need a 3rd part about normalization 🥹🥹

[matyasblaha]

awesome! awesome! awesome!! Thank you! :)