Database Lesson #2 of 8 - The Relational Model
HTML-код
- Опубликовано: 29 май 2013
- Dr. Soper gives a lecture on the relational model and its role in the database world. Topics include relations, primary keys, composite keys, foreign keys, normal forms, and the normalization process.
00:19 Topic Objectives
01:37 Entity: represents a single theme or concept with which we want to track its attributes. e.g. department, employee, or project.
02:43 Relation: a relation is a type of table. Relation table characteristics: rows contain instances of a table, each column is an attribute, each column are of the same data type, each column has a unique name, cells of the table hold only a single value, no two rows can be identical, the order of the rows and column do not matter.
08:28 DB terminology synonyms: table = relation, row = record, column = field = attribute
09:40 A key is a column(s) of a relation whose values are used to identify a row
11:45 Topology of DB keys
12:09 Composite key: unique key, composed of two or more columns.
15:12 Candidate key: unique key, has potential to become primary key.
15:50 Primary key: unique key, main key for identifying a specific row in a table.
17:35 Surrogate key: unique key, added to a relation to act as the primary key.
19:20 Relationships between tables
19:30 Foreign key: non-unique, a foreign key is a primary key from one table placed into another table so that the tables can be linked
22:48 Referential integrity ensures foreign keys refer to actual entities in another table
25:30 Null value
30:32 Data normalization: process of analyzing a relation to ensure that it is well formed (i.e. not susceptible to anomalies)
37:02 First normal form: table contains no multivalued attributes. Every attribute value is atomic. Thus, all relations are in first normal form.
39:13 Second normal form: 1NF + every non-key attribute is fully functionally dependent on the entire primary key. i.e. we can't have partial dependencies among attributes of the table.
43:32 Third normal form: 2NF + no transitive dependencies
are you related to Jim Rohn?
thanks
thanks a lot mate
That's really useful ! Where I can find the PPT form?
thanks Rohn for breaking it down
This IS the best video I've ever watched for a college class. You are explaining the whole chapter about relational models in depth without skipping over any information. I WISH you were my teacher.... Thank you for saving another student.
these videos from Dr. Soper seem excellent to me. His tone and demeanor are relaxing and conducive to learning which I appreciate. No adds - he is not trying to sell something . thank you
The best database course on RUclips. Well balanced and well explained.
the enthusiastic voice also helps shred some of my depression crumbs.
I've learned a lot from this lesson as well as L1 and willing to continue to learn until the end of this course. In the meantime, thanks to Dr Soper for this impressive free course of his.
By far the GREATEST lecture on the topic. He has such a deep understanding of the learning curve.
I am luck to watch your lectures as my first step into DB world. Thank You Sir.
THANKS VERY MUCH!! I HAVE TAKEN 5 DATABASE LECTURES IN COLLEGE, AND I LEARNED NOTHING FROM MY PROFESSOR. YOUR LECTURE VEDIOS TAUGHT ME EVERYTHING!
Very helpful, clear explanation of topics that confused and bored me to tears. It still bores me, but at least I now understand it. Thanks.
This is by far, the best introduction to Relational Database, I am reading these monster books about this subject and sometimes have to read it 3 or 4 times and still not fully understand some of it. But these lessons are great and understandable, So thanks a lot for your great work with this. :-)
I feel like a well done videos is a much more digestable than any book. The visuals being displayed while being talked about helps so much for me. It's so annoying having to flip back and forth from text on one page and diagrams on another, and trying to make sense of what's being said.
@@andrewting3081 The longer a sentence the harder it is to follow in in written form, at least in the english language I find. So the moment pronounciation and flow get mixed into the equation it's so much easier to follow along
This whole series is awesome. I have seen lessons 1,2 and 4 and I feel very prepared for my DBMS exam. I feel like I understood the concepts so much better than what I have in a month in class.
I DONT THINK THERE IS A WORD IN MY THE ENGLISH VOCABULARY TO THANK YOU SIR.
YOU ARE AN AMAZING TEACHER. :)
The best Instructor and the best Basics of Database tutorial, that I’ve seen so far on the social media.
We really appreciate it.
Thank you Sir Dr. Soper
Simply superb. Highly appreciated. Full respect. I have learned a lot. Can't thank you enough Dr. Daniel Soper! My best regards.
This is a very good lecture for a beginner of database learning. Thank you Dr.Soper.
Another great video. I tried so hard to understand normalization so many times with other instructors and you perfectly summed it up in a perfect way for me to get it.
I read two textbooks and couldn't learn this stuff. You are helping to make online school doable and in the process saving me thousands of dollars and hours of time. I thank you.
These lections are pure gold, big thumb up !
These first two video parts summed up around 8 hours of lectures in school, and I learned even better from these two videos
2nd ! 6 more to go and my head will be full of usefull information Thanks again !
These videos are how I'm passing my Data Management Foundations course at Western Governor's University
The best DB lecture I have ever watched. Thank you sir.
You should write university textbooks. The current material out there there is vague and doesn't explain the terms in real terms.... You are a brilliant lecturer Doctor D.
I agree! The money he would make from selling the textbooks would be deserved.
Really great videos.
I'm a .NET developer with 4 years working experience, but still find your lectures very helpful. You helped me re-think and clarify many fundamental concepts.
Thank you Dr.
Awesome, just awesome the way you explain it, so it can be understood and you give everyday examples.I've looked at video after video and finally found yours. I was struggling now I'm starting to get. And this is just the 2nd video. THANK YOU
For some reason my lecturer decided to split the normalization (1,2,3) into i think 4 different lectures and he made it look so dificult, i managed to fully understand it from you in few minutes, thank you! and keep doing this great lectures
This is really really well taught. I am not a programmer nor do I have formal programming training, but I have a passion for it and my programs only depend on small data files like .jsons or .py files which are updated and their contents reimported to the program on its next instance. For someone without much experience, the thorough and concise way you explain things makes it very easy to follow and expand my knowledge really quickly. I cannot thank you enough for posting this lecture series.
This is an incredible tutorial, thank you Dr. Soper
What a GREAT resource for anyone learning Database concepts. THANK you Dr. Soper
I failed DB in College many times.
After 3 years of DB, I had learned and understood more from this than what my lecturer had taught me...
Maybe that says more about me, but that class killed me, this makes DB interesting to me again.
Thank You!
Screw the three that disliked this video, this is great content. Thanks for posting!
Dr. Soper, thank you immensely for your contributions here. The textbooks I was going off of to learn this stuff are not of the best quality and you make it quite simple.
Thank you for posting this video. I am happy that I could find one with a perfect English accent.
JeanAlesiagain3 I know the pain you went through. lol
this presenter is much clearer than a lot of actual uni lecturers...
I've learned also a lot lot whole lot from this lesson. I am watching all of them. Dr SOPER is SUPER.
I was trying to find materials on databases concepts and this is one of the best video lectures i have seen by far.Thank you sir for the wonderful lectures.
Thank you Dr. Soper....this series is proving extremely helpful.
These videos are very professional in every sense. Can't find better videos than these on this topic.
You are truly amazing! You explanation are so clear and easy to understand. Thanks a ton.
Very helpful, thank you Dr Daniel.
Very well done, thank you much as I'm going to watch the whole series.
OMG your lectures are best simple and detailed anyone who never had heard of data base can come and learn here , plz keep these coming , we will support you :-)
This is great stuff. So easily explained it's opened my mind.
Simple and easy to understand. Also very useful and essential for begginers.
God damn. Two videos in and I already learned more in less than two hours than I did in two months of my college course in data management...
Thank you Dr Daniel Soper.
Your voice is so good! I pair your lessons with some lofi and its just so smooth. Very easy to focus on.
Brilliant. Very brilliant. Thank you Dr. Snoper. I am currently using this in my class.
I'm so glad to watch your tutorial, it give me a deep understanding about DB world.
Thank you Sir.
Lots of examples, thanks for this very good educational work!
Amazing content!!!!!!!!!!! Coherent, clear and extremely easy to follow.
Thank you, doctor Soper really this is excellent course until now I see before,appreciated
Extraordinary explanation. Thanks a lot Dr. Daniel.
The best teacher ever!
Thank you for these videos! They make my classes so much easier to learn!
Thank you for the high quality lectures.
So many new things in this video but you did it well, just a little bit carefully read again and then i can get what you describe!! Nice job
These videos are amazing. Thank you.
Awesome! very clear information and in a simple way.
Exquisite! Really thorough and helpful. Thank you!!!
I find it very interesting & understanble in all your tutorial. I'd really like and happy to follow all your tutorial❤️❤️💯
Very, very good explanation. Thanks a lot Dr. Daniel Soper.
Thank you Dr Soper. This is really educative.
OMG THANK YOU SO MUCH!!
I wish my lecturer will be as good as you when explaining something!
These lectures are really, really good. Thank you!
Alot better explanation than university professor. Thanks 😊
It's as clear as the first part :) Thank youuuuu
Thanks for the course, and the subs!!
Great videos with proper details. Thanks a lot.
Thanks you Dr. Soper
Perfect perfect perfect
thank you Dr from Saudi Arabia
Thanks a lot, you are such a good teacher!
Thanks for explaining so well.
Nice video. It help me so much to understand the concept of this topic
Brilliant. Very brilliant. Thank you Dr. Soper. I am currently using this in my class. Sorry that I spelled your name wrong in my first comment.
Great videos, I have learned lot from this videos. If possible can you please share PPT.
Thanks Dr. Daniel Soper.
If anyone was confused by the 2nd Normal Form definition like I was, I think I got it now. In the example at 40:00, the primary key is a composite key - which means we are using not just one but two key columns to determine all of the other non key columns. The problem is, we found that there are some non-key attributes which don't need both keys to determine their uniqueness. We found that just one of the keys was sufficient for them. So, why not break down the table by removing those non-key columns which only need one of the keys and put them in a separate table where they can be ruled by that one primary key while in the original table only those non-key attributes which truly need to be defined by both key attributes should remain with the entire composite key.
GREAT LESSON! THANK YOU
THANK alot ur making things nice, natural and understandable.
Formidable!... So gratefull !... Thanks a lot.. But need to watch again.. ;)
Thank you Dr Soper
Great Lesson. Thank you.
Excellent! Love the normalisation part. Only one issue, a foreign key does not need to point to the primary key, as long as it is pointing to a *unique* column...
Technically, that is not all of the story either. A foreign key can reference multiple columns, as long as together they are unique in the referenced table. For example, table A might have a primary key that is a composite key. A foreign key in table B that references table A would then have to reference more than 1 column in table A.
I am so happy to attend your lectures
Great content, thank you.
Great lecture!
it's strange, because when my lecturer was explaining the exact same thing, I was so confused on what the hell was he on about, but when you explain it, it makes sense to why there's a Database, a database management system , database application, why the relationship table is defined that way etc
What I like to imagine with normalization is breaking and rearranging columns and tables to be the most efficient. Having multiple values in a box is very inefficient because you'll never know which item to choose. So that's N1
For N2 the only thing I can see is that you rearranged and split tables for higher efficiency, put Products together, Put Orders together
For N3 Instead of having Customer Id, Customer Name, Customer Address as part of Order, you put these attributes as a table itself and referenced it once in Order table
you are the best...it is very useful
Amazing videos!
Thank you! Very helpful indeed
Awesome best uptill leacture on database
Very nice! Thanks.
Amazing.... Thank you sir
Many thanks for these videos
Very good lessons, Thank you sir.
You killed it..Thanks you
I'm in the middle of a Database Management Foundations course. I am so thankful for finding your videos! the reading material is so dry. I'm still having a hard time with normal forms though.
WGU C175? Agreed.
@@_stuckinga yep. I failed the first OA by like 4 questions. Ugh
it is considered to be the best approach for the beginners. i found some personal issue while hearing out this. He was quite slow in delivering most often i went for yawning and lied for long sleep.. :p anyways Dr. praised for ua t ur best delivered approach......
This is extremely nice content.