Database Lesson #4 of 8 - Data Modeling and the ER Model
HTML-код
- Опубликовано: 9 июл 2024
- Dr. Soper gives a lecture on data modeling and the entity-relationship (ER) model. Topics include the components of ER models, depicting entities, attributes, relationships, and cardinalities in ER models, one-to-one, one-to-many, and many-to-many relationships, strong and weak entities, identifying and non-identifying relationships, supertypes and subtypes, and recursive relationships in data models.
Dear Dr Daniel
I just wanted you to know
That I am a computer science student who lives in Syria
With very Poor financial conditions so I cannot afford for private tutors to teach me dbms
I'm so grateful for the high quality knowledge you provide here for free
Words cannot describe how thankful I am
Wish you all the best
please keep us updated on your progress. Us here are interested in how you end up!!!
I appreciate your kindness, the situation here is very bad in all aspects, unfortunately I'm just doing the bare minimum to pass my courses at university, the electricity here is available only 3/24 (three hours a day at its best), I think I'm graduating next year, but I think its hard for me to get to the real job market, I may start learning web development (in case things does not go worse!!). thanks for your comment again it made my day, wish you a nice day @@dgenerationbigestfan
Requirements to ER model
5:15
Entity class v entity instance
6:50
Entity class v entity instance visual
10:30
Attributes
11:20
Identifiers [keys]
13:10
Types of keys
13:50
Level of entity attribute display
16:45
Relationships
18:50
Conceptual unary relationship
21:20
Conceptual binary relationship
Conceptual ternary relationship
One or many connections
23:12
One-to-one binary relationship
24:10
One-to-many binary relationship
25:00
Conceptual many to many binary relationship
Note: can’t build a direct conceptual many to many in a db. Need
a middle table….extra entity
25:40
Conceptual many to many binary relationship/ extra entity
26:50
Maximum cardinality
27:20
Minimum cardinality
28:40
Crows foot symbols
29:20
Cardinality example
33:20
Er diagrams
34:40
Has -a-relationship
36:00
Strong and weak entities
36:30
Id-dependent weak entities
38:00
Weak entity relationships
40:00
Weak entity identifier/ non-id dependent
41:30
42:10
Subtype entities
44:00
Subtype entity identifiers
47:30
Subtype entity examples
Recursive relationship
53:00
Hero status unlocked!
You dropped this crown, @Warren L.
You're better than my prof. I've been anxious about this class because the lectures cover just spouts of info and not the details. Thanks for this!
Paying 9 grand for uni and get a useless pdf as a resource. Pay nothing for an hour long, detailed, easy to understand video. This is just so wrong
i feel you
Fedil Al-Hayawi That's the new model of education. The same thing happened to me. I got a book of data base design from the library, Too complex for a beginner, but this video make thing easier.
+Fedil Al-Hayawi It's a f***ing scam. I decided not to buy any textbooks this semester (except for one that I found an older edition for $5).
It's so frustrating, they release new editions every couple years, and the only thing that changes is maybe the introduction and the end-of-chapter questions! And then when you finish the course, a $250 book is suddenly worth $60. Better to rent, but it's still a rip off.
About to graduate, and the whole time I'm thinking when I walk the dean is going to hand me a paper, saying "here's your receipt".
well said!
I understand you bro. It can be that bad.
Thank you so much Dr Soper; this is hands down, the best ERD tutorial I've ever watched. Great job!
Thanks a lot Dr. Soper, best coverage on the data modeling and the entity-relationship (ER) model I have ever seen. You are one of the best teacher I have ever had.
Dr. Soper, you are a great teacher. The content is so clear and easy to understand, the way you explain things is so logical, and your examples really help. Thank you for this!
I've taken 2 database classes in the past but I've learned so much from your series of videos than I've learned in the classes, very detailed and easy to understand, thx u so much.
If it must be done, It must be done well. Dr. you did it all . from simplicity through clarity to comprehensiveness. Bravoo!!!!!
At 20:56 I was having difficulty with the Person entity relating to itself with marriage. I was thinking “Aren’t 2 different entities getting married?”.
Then I resolved the difficulty by realizing that A person entity is a table. While an employee table relating to a parking table is a binary relationship because it involves two tables, one person instance getting married to another person instance is a Unary relationship because it involves just one table which is why we also call it a reflexive relationship.
Love everything about your lectures - the pace, the material, the structure, presentation and also the manner of speaking. Huge thanks!
Saved the video in 2018 and watching in 2022. What a gem! Thank you so much, prof.
Dr. Daniel Soper, thank you so much for this. This is by far the most clear, lucid explanation of data modeling and ERDs I've come across. Fantastic!
Your method of presentation is second to none and your explanation is top notch. You deserve an award. Thank you!
This is the best tutorial on this topic you'll find on the internet
This is gold. The best lessons on RUclips.
I thank God for creating people like you.
a joy to refresh and learn with Dr. Soper. Thank you!
Just came across your tutorials today after years of many challenges learning databases.
I'll return to give feedback.
Very positive comments so far about your work.
Thank you
This is a great addition to my non-lecture database class. I will recommend it to my class. Thank you.
Kimberly wow. How easy is it being a teacher?
Very clear and concise. Video elaborates on specific details that are critical to understanding the subject matter. A+ quality. Deeply appreciative of your generosity!!!
Thank you Dr. Soper for this presentation. It has been a great help!
Thank you for these videos, they have been incredibly helpful.
Thank you Dr Soper. This is really amazing. God bless you.
Very smooth and understandable explanation. Thanks a lot.
That is is great lecture I ever had before. Thanks very much Dr. Soper.
Dr. Soper, this is excellent. Thank you very much.
this is the best video on Data Modeling . very clear and explanatory. well done prof.
Thank you so much Dr. Daniel Soper.
You have a teaching gift - like many others who have furnished a response - I currently study this topic at University. The teaching at my facility just isn't up to this standard when it comes to imparting concepts this clearly...I am almost at the end of your fourth video and feel I have such a good grasp of the concepts involved. Thank you
Dr. Soper thank you for this great video series.
I have studied all those things at the university and I had no idea what the heck I was studying. I could barely get B0 (B-) for all preparing tests and exams with many not sleeping nights. I was just happy not to get FAIL.
I have been watching this video with 1.5X speed and can't believe everything is so well explained and easy to understand!)
37:07 "Any entity that is not a weak entity is called a strong entity" Very helpful.
I appreciate your careful systemic explanation
Why hasn't my prof done anything like this? I'm having to scour the internet to find a lecture on the subject. My professor just has us read the book, then gives us assignments. He offers no other learning resources whatsoever. Thankfully I've found this.
Same here
My professor doesn't even speak to me. Been asking about what I should do. I get this video. This isn't even on the chapter I am learning.
My lecturer just gave us a pdf, which were slides from THIS series. huehuehe
Great,perfect explanation.One of the best video tutorial in the youtube I have seen,I improved my Englilsh also as an extra benefit.
Valuable learnings keep life FRESH😊 Thank you for your valuable lessons🙏
Very useful.. Explaining it in a very simple way.. Thank You Dr. Soper.
Excellent. Explanation is so simple and effective.
Thanks for all you do;
I am very stoked on these videos.
Thanks a lot Dr. For this really informative lecture. Have a good day
I have no formal training on IT.yet these lectures give me an insight into the IT world...Thanks...from Nepal.I am learning a lot...
Thank you so much Dr. Soper!
Amazing series Daniel! Thank you very much
Dr Soper.. thank you very much for knowledge.. u made things so simple ..wow :)
You are an awesome teacher!
Thank you so much Dr.Daniel Soper, this is the best use full and understanding lecture I never had i'm thank full! if you have more continuing database lesson 9 Ext
Dr. Soper you are a life saver
Great presentation; well-spoken and thoroughly informative. Will definitely utilize your videos to supplement my AIS course!
Thanks god for a video in RUclips I can understand
Thank you for this presentation, this was very helpful.
Very informative lecture . i was able to understand the data modelling in much better way. Thank you sooo much for making such a great video with great explanation. :)
Great man done great Job. Thanks Dr. Soper
I took introduction to Oracle SQL and this is bringing it all together for me.
Awesome series. Thanks so much!
Thanks a Million Professor!!!! God bless you.
Thanks for the excellent presentation!
Great work on the video series. Very informative.
Thank you Dr. Soper!
Thank you for this amazing lecture series! One feedback- I'd love to see more examples of how to read the diagrams depicting entity relationships- You explained the concept well but some more examples would help the viewers
thank you dr for this amazing content
Awesome vid! Now I understand the giant 20-30 entity diagrams in my work.now All I have to do is memorise them!
that's really amazing God bless you
Very helpful! Thanks a lot for sharing!
wow, in this way (and length) every youtube video lesson should be. Nice!
Well done, Dr. Daniel Soper.
Great Videos and Very informative for building good concepts. Thanks.
Writing business systems and analysis test in 12hours, thanks to Doc im gonna nail it
very well explained Data Modelling and Entity Relationship Model. Thank you
Thank you. Very well explained.
Thank you for the lesson!
Thank you Sir. This is still relevant and informative in 2019
3w553ree555sr43w553ree554445sr554 5r5545 and 5 I 4354noon err e4t4t3 tt4rr44 koi544 55555inches3zwdxx'r5was342455ss55sssssssssxcxv554ewd5xx'r 35 the 5same of 2444 re 445w55 i re6,655s6tr56t6 rut 66 rut 66666666666s66s6 ttrr tree error r76 Stewart 3ewe7sfor or rate w5r÷6d5a5sa5eew ee6 55w5wr55e6 w5w5wr55e6 a week 5w
very very useful, and easy to understand and in easy language. thanks
Thank you so so so much!!! My textbook is written poorly. Also, I now even understand objects and classes better. Thanks!!!
Thank you for the video.
very nice video! thank you for taking the time to share your knowledge. However, I had to speed up to 1.5 as i found it to slow but that is probably because i had too much coffee. Works like a charm
*DR. SOPER* , I am learning a great deal from your lectures! I believe I found a small mistake at 52:52 and 55:03. In the recursive (unary) relationship between employees and managers, an employee need not have a manager (e.g., the CEO has no manager), but each manager must supervise at least one employee _and may supervise many employees._ So, the crow's foot symbol next to the employeeId attribute should have a cardinality of *one-to-many* , not one-and-only-one. Is that correct? Thank you!
I have the same question.
Who asked you id_ot
@@thomasjust2663, if another person's intelligence, knowledge, and ability make you feel so threatened, inadequate, and inferior that you become rude and insulting and lash out for no reason, then you have a real problem. You need to get help with that. I want you to talk with someone you trust, like a close friend, counselor, or therapist, to figure out why you are so desperately unhappy. You'll never find happiness by trying to tear other people down. You need to believe in yourself, invest in yourself, and build yourself up. I did it, and you can do it too. Will you try, Thomas?
I think you are right
p
9
Great presentation.
Thank you
thank you very much !! very clear tutorial
Thanks, Professor.
Great Lecture
Great videos!
great explanation!
i learned alot! Thanks :)
Thanks very much for your lecture. I was able to connect a lot of dots. Would you post the slides - the examples help when trying to model parallet db schemas in my own work. Thanks again.
Thank you Professor
Excellent presentation
The guy is great!
Perfect!
For the last example, the diagram reads that an employ can have ZERO OR ONE manager (with which I agree) but a manager can have EXACTLY ONE employee (showed with the two hash marks) which the following illustration clearly proves wrong (as a manager had three employees under him) Did I miss something?
Well asking the question I think I answered myself - managerId can be NULL, but a managerId HAS TO be one and only one employeeId
For the model you showed with undergraduates and graduates, how would you prevent losing the data about a student who goes from undergrad to graduate considering each one has their own specific attributes?
Question: If the PK of the strong entity is not a FK in the weak entity, and all other restrictions remains the same, would it be a non-id-dependent relationship?
great presentation it was helpful
Thank you!
Very helpful teaching presentation, above all I admire your good intention for sharing it with the public. Is there any other subjects or topics on your agenda? - Thank you.
great video.
superb!
This series was highly recommended to supplement my DBMS course....but that microphone static in this video is incredibly distracting.
why do you have to acknowledge recursive relationship ? empId implies managerId so why does it have to be marked ?