How about I train you on the foundations of Data Modeling? Email me at "ReachBinduKumar@gmail.com" or Telegram at @ReachBinduKumar to sign up for my Live Instructor Led course on "Data Modeling Foundations". I am a Senior Data Architect with over 18 years of real world experience designing Data Architecture for a variety of use cases. See you in my class!
The best explanation of the 3 stages of a data model that I have seen anywhere. Definitely worth a watch. I've just revisited as a refresher now that I'm working in master data management. Thank you for the great video.
So here's what I understand, I wanna know if it's correct please: Conceptual data models are like the general overview of how the actual data model should look like, like a sketch for a painting or an architecture. Logical data models are idk, more complex? They basically have key and non-key attributes to the entities now and primary and foreign keys can be used. It's still easy to understand, but is harder to update because it's more complex. Physical's simply like, full-fledged. Entities are called tables, attributes columns, it's even harder to understand and really difficult to change.
Yes, that is a pretty good summary. I am compelled to add just one additional detail to your explanation. The physical data model, apart from being full fledged, is specific to a database, like Oracle or Postgres or SQL Server etc.
Thank you for explaining this! It makes soooo much sense from your POV. My University did not make our weekly lecture notes this simple to understand. Again, thanks dude
Hats off to you...you made it so easy to understand...i used to have very confusion between conceptual and logical data model...but your explanation cleared all my confusion... Thanks a lot..
The way of your explanation has helped me distinguish all those data modelling and gain me a clear understanding, now I can go in deep to study these modelling.
This was explained and presented very well. Extremely helpful. Thank you for creating this video. I took some practice tests for the Microsoft Database Fundamentals Exam (98-364). Now I feel like I really understand the parts that I needed to work on.
Thank you Renee, for your encouraging comments. In case you found any issues with the audio of this clip, there is a version with improved audio, here --> ua-cam.com/video/cY7WZYhyC3o/v-deo.html Please do subscribe in case you haven't. Thanks !
@@ChilaKasonde I am not an expert on this topic, but it doesn't seem very different from SQL queries on a database. Allow me some time to get back to you with more details.
As an analytics engineer, having realised the downstream cost of a bad data model design, I can totally understand the need for having a structured approach. Thanks for the video.
@7:53, in the Product table, isnt Category Description dependent on the Category and the Category is dependent on the ProductID? That would mean the Product Description is transitively dependent on ProductId? That means it wouldnt pass 3rd normal form, right?
You are absolutely right, but in this example the data model being represented is a "Dimensional Model". In a Dimensional Data Model, Denormalization of data is normal. Hence it is fine to keep both Product ID and Description in the same table. Great Observation 🙂
does the sales table in this example have a primary key or not? It uses 3 foreign keys but they are above the line so am a little confused whats going on there.
Hello. Regarding your question. Your observation is right. There are 3 foreign keys in the Sales table. They are 3 foreign keys, but at the same time, all 3 together are used as Primary Key as well. Your question is arising probably because, you assume that only one column is used as a Primary Key. But that would be incorrect. A Primary Key for a table can be a single column or a set of columns. In this example, a set of columns is used as the Primary Key, because that is what is used to uniquely identify a record in the Sales table. Hope this helps !
Do you have any video which explains conceptual model? I have a question. In conceptual model, can two entities be associated with both direct and indirect relationship? e.g. engineer inspects item. This inspection generates inspection report. So entity 'engineer ' can have a relationship 'inspects' with entity 'item'. Also entity 'engineer 'can have a relation 'conducts' with entity 'item inspection'. Entity 'item' will have a relationship 'undergoes' with entity 'item inspection'. Is it valid?
Hello Rupa. Apologies for the delay in responding. To your question - Q: Do you have any video which explains conceptual model? A: No, I do not have any specific video just on the Conceptual Model. I will probably upload in the near future. Q: In conceptual model, can two entities be associated with both direct and indirect relationship? A: Yes, you can have a direct as well as a indirect relationship between entities, as long as it is meaningful for the person reviewing the model. Ideally it is the Business/End User who is reviewing the Conceptual Data Model. In case it makes the model complex or the direct/indirect relationship only exists as an implementation outcome (physical data model), then it is best to leave it out of the Conceptual Data Model. Hope these answer your questions!
Is it mandatory to use tools to create data models? Can't we do it manually without using any tools? Will it create a bad impression in the interview if I say I haven't used any DM tool? Thank you!
Hello Sneha. It is not mandatory to use a Data Modeling tool, but it is hard to ignore the benefits it brings. Regarding interview, even if you don't get a chance to use a Data modeling tool at work, you can always get some hands-on outside of work. Once you are confident, you could say that you have indeed used a data modeling tool. But remember that, a data modeling tool doesn't necessarily improve one's data modeling skills. It merely eases the overall modeling process. Hope this helps !
@@DataAcademyIN oh its ok sir, can i also no is it ok if use the world design insted of model ex- conceptual database design , logical databas) design)
It looks like I was learning different data modelling methodology 😃 1. logical model, called also Entity Relationship Diagram (ERD) represents entities and main relations between them, has usually primary keys and some main attributes as well, entity is drawn as a rectangle with rounded corners, and entity name is always singular, an entity is one instance of something, 2. physical model, called also as Data Diagram (DD) is generated from ERD also FK columns are added automatically, other columns can be added to the DD manually as well as other UK, indexes and partitions, entities are called tables, attributes are called columns, table is drawn as a rectangle with sharp corners, having a well designed DD we can generate table creation scripts so no manual work is required from developers, table name is always plural, a table is a collection of entities, 3. we should avoid adding a table name to table column names, table product should have columns description, name, short name, size... but not product_name, product_description, product_size...
"not product_name, product_description" - depends. If the target of the model is reporting, you would end up with 10 columns all called "name" which is confusing and you would spend ages renaming each column in the report. Much better to give them full names. The other advantage of having the table name is if it is a foreign key, you can use the target table name (with role if needed) e.g. "Product_Id,Product_Code,ProductGroup_Id" or "Customer_Party_Id, SalesRep_Party_Id"
@@MrAndrewjdavis yes and no :-) if you want to distinguish columns from different tables, you can use table and column aliases, it takes a bit more work but it is better in my opinion, also a column name like "Product_Name" looks ugly on the report for end users, usually it will be renamed as "Name" or "Product name" on reports, not to mention that reports may be created in other languages, what people from English-speaking countries forget often, databases are usually built in English as they are often created by international teams, while reports are created in accordance with local requirements and often have to be created in the official language of a given country
How about I train you on the foundations of Data Modeling? Email me at "ReachBinduKumar@gmail.com" or Telegram at @ReachBinduKumar to sign up for my Live Instructor Led course on "Data Modeling Foundations". I am a Senior Data Architect with over 18 years of real world experience designing Data Architecture for a variety of use cases. See you in my class!
The best explanation to someone that is just starting off in DBMS. Great job on explaining this in detail!
Thanks George! Your comments are very encouraging :)
I agree, thank you so much!!!
q@@anon12416
this is the best DATA MODELLING TUTORIAL i have ever watched. What an explanation good job sir.
Thank you Raviteja for your encouraging comments ! Please do subscribe.
The best explanation of the 3 stages of a data model that I have seen anywhere. Definitely worth a watch. I've just revisited as a refresher now that I'm working in master data management. Thank you for the great video.
Thank you for your encouraging comments Jordan. I am glad you found it useful. Do subscribe to the channel.
One hundred percent more thorough and engaging than a textbook. Thank you my friend!
Thank you Lo Green. Please do subscribe !
So here's what I understand, I wanna know if it's correct please:
Conceptual data models are like the general overview of how the actual data model should look like, like a sketch for a painting or an architecture.
Logical data models are idk, more complex? They basically have key and non-key attributes to the entities now and primary and foreign keys can be used. It's still easy to understand, but is harder to update because it's more complex.
Physical's simply like, full-fledged. Entities are called tables, attributes columns, it's even harder to understand and really difficult to change.
Yes, that is a pretty good summary. I am compelled to add just one additional detail to your explanation. The physical data model, apart from being full fledged, is specific to a database, like Oracle or Postgres or SQL Server etc.
Seems you got a tight grasp on the data modelling, I'd define it the same way you did.
best video available on youtube for understanding Data modeling.
Wow even after few years this is still saving lives!!!
😊
Great video, just the right depth of coverage, optimum length to keep the viewer engaged. Thanks for taking the effort to prepare and share this. 👍
Many thanks for the encouraging comments Amit! Please do subscribe to get notified of new videos.
The best tutorial for data modelling. I have interview ahead and this video is really helpful.
Thank you for your comments Alip. All the best for your interview!
Please do subscribe.
Just started my way off with DBMS, being a Mechanical Engineer after going through this, I feel I am in this field since years! Great lesson😌
Thank you for your comments Daksh! Happy Learning :)
Thank you for explaining this! It makes soooo much sense from your POV.
My University did not make our weekly lecture notes this simple to understand.
Again, thanks dude
Thank you for your encouraging comments :) Please do Like, Share & Subscribe
Hats off to you...you made it so easy to understand...i used to have very confusion between conceptual and logical data model...but your explanation cleared all my confusion... Thanks a lot..
Thank you for your feedback Jaya. Please do subscribe !
Thank you for such a clear and accurate explanation of the different database modeling stages
Many thanks Julio. Please stay subscribed to support !
The way of your explanation has helped me distinguish all those data modelling and gain me a clear understanding, now I can go in deep to study these modelling.
Thank you for your encouraging words! I am glad you found my explanation useful. Please do subscribe!
Just a great video for beginner who want to understand the data model. Thanks for such short but very useful concepts
Many thanks for your comments Lal Bihari Prajapati. Please do like, share & Subscribe.
O Goodness! This is the clearest explanation I have come across. I think this will stick as well.
Thank you @joankwamboka700. I am glad you found it helpful. Please do Like, Share & Subscribe!
This explanation is the best. so easy to comprehend...kudos
Glad it was helpful! Please do Like, Share & Subscribe
Great and simple explanation sir. It saves lot of time from reading theory sometimes
thanks because it brings clear description from start to end.
Thank you Muhwezi. Please do subscribe !
Your teaching is clearer than my lecturer , thanks alot man
Glad to hear that
This was very detailed yet very simple explanation. Thanks a lot Sir.
Thank you Ankush for your comments :) Please do subscribe !
This 13 min video explains one hour lecture. Thank you
:) Thank you for your sincere comments !
This was explained and presented very well. Extremely helpful. Thank you for creating this video.
I took some practice tests for the Microsoft Database Fundamentals Exam (98-364). Now I feel like I really understand the parts that I needed to work on.
Glad it helped! Please do subscribe !
Best video for understanding the types data modelling.
Thank you Sathish for your comments. I am glad you found it easy to understand. Please do Like, Share & Subscribe!
Best explanation I’ve ever seen for DBMS
Hello Kadi. Thank for your comments. Please do subscribe to support the effort. Do browse my channel for more such videos. Cheers !
Very clear explanation of the topic...really appreciate it.
Thank you Ömür for your comment. I am glad you found it useful. Please do subscribe!
Thank you for such a great explanation with visual examples. This helped me greatly.
Thank you Renee, for your encouraging comments. In case you found any issues with the audio of this clip, there is a version with improved audio, here --> ua-cam.com/video/cY7WZYhyC3o/v-deo.html
Please do subscribe in case you haven't. Thanks !
Wow, great video. I tried to read about data models and was 100% lost. Now I 100% understand after watching this video.
Happy to hear that Nicholas :) . Please do subscribe to get notified of new videos. Cheers !
this is the best explanation ever. You solve my problem
Thank you Juvette. Please do subscribe!
you explained it in a great and plain way. Thanks.
You're very welcome!
Thank you so much for such a wonderful explanation…. Brief and crisp!
Thank you for your encouraging comments Jyothy. Please do subscribe !
Just wanted to thank you my Lecturer did a terrible job explaining these to me , i now have a clear picture of all 3 models thank you
Words can't describe how encouraged I feel to hear such comments. Thanks for watching. Do subscribe!
@@DataAcademyIN ive subscribed keep up the great work, do you have any material on Relational Algebra?
@@ChilaKasonde I am not an expert on this topic, but it doesn't seem very different from SQL queries on a database. Allow me some time to get back to you with more details.
@@DataAcademyIN thanks will be waiting i think it would be a good video as no one has covered it from what I've seen
Very helpful. Clearly defined each and every models !!!
Thank You Nikunj !
As an analytics engineer, having realised the downstream cost of a bad data model design, I can totally understand the need for having a structured approach. Thanks for the video.
That is very well said Pratyush. I am glad you realize the importance of a Data Model well executed.
Please do subscribe !
@@DataAcademyIN Done already, keep spreading the knowledge :D
very simply explained and easy to understand. Thanks !!
Many thanks Lavanya. I am glad you found it easy to understand. Please do subscribe to get notified of new uploads. Cheers !
Very helpful and informative, Please keep educating people. God Bless.
Thank you for encouragement KoloHe. Appreciate it. Please do subscribe !
You did a good job here. Your diction and pacing were perfect. The diagrams were simple and complete. Thanks.
Thank you John for the encouragement. Please do browse my channel for other videos. Do subscribe to get notified of new uploads. Thanks !
This is actually really good explanation.
Thanks Gunjan !
Wonderfull explanation Sir. Thank you very much for making the video.
Thank you for your comments Sudarshan !
Best explanation for these 3 models
@7:53, in the Product table, isnt Category Description dependent on the Category and the Category is dependent on the ProductID?
That would mean the Product Description is transitively dependent on ProductId? That means it wouldnt pass 3rd normal form, right?
You are absolutely right, but in this example the data model being represented is a "Dimensional Model".
In a Dimensional Data Model, Denormalization of data is normal. Hence it is fine to keep both Product ID and Description in the same table. Great Observation 🙂
@@DataAcademyIN
Thank you. It has taken me a while to learn this stuff but I’m slowly starting to grasp it. I appreciate the videos 🙏
Very simple video, but extremely clear: it helped a lot before digging into more detailed tutorials. Great work indeed.
Thank you Fabrice ! Please stay subscribed to support !
@@DataAcademyIN : Of course !
Big Thank you Sir for such wonderful explaination!!!
Waiting for more video with some business cases
Awesome video. Very Explanatory.
Thank you Arun. Please do subscribe !
Very useful video. Thanks for your efforts in sharing this knowledge.
Thanks for your comments Ravi :) Please do subscribe for supporting more such content !
Hands down the best Video out there.
Much thanks SaiKiran :)
Simply the BEST. Thank you!
Thank you Evelyn. Please do Like, Share & Subscribe!
Absolutely brilliant video. Thank you sir! 🙏
Thank you for your comments :) Please do Like, Share & Subscribe
very helpul and conceptual video. Thanks a lot buddy.
Thank you Asad !
Thanks a lot going for an interview tomorrow this explanation saves me lot time in understanding 😆👍🏻
Thank you Raghavendra ! I am happy you found it useful. Do subscribe !
Really good one for beginners to understand easily
Thank you for your comments Karuna. Please do Like, Share & Subscribe !
Thank you for simplifying this.
Thank you for your comment :) @luckymuchaka3523
excellent video! thank you very much!
Thank you for your comments. Please do subscribe!
I appreciate your efforts to prepare such a wonderful video!
Thank you for your encouraging comments.
Wow.. clear explanation with diagrams.
Thank you Dinesh !
Excellent explanation. Short, sweet, and to the point while covering all the essentials to data modeling. Thx you😉
Many thanks for your honest comments. Please do subscribe !
Very helpful, clear and detailed! Thanks a lot.
Thank you Sarah ! Please do subscribe for more such videos. Cheers !
Big Thank you sir for such a wonderful explantion......waiting for more video wid business cases
Thank you Nita for your kind words :) Stay subscribed to get notified of new videos when I do upload. Pretty soon.
Very well explained. Thanks !!
Thank you Charu ! Please do subscribe.
Thank you so much. This was very helpful.
Glad it was helpful!
such a clear description, thanks
Thank you Itishree for your comments. Please do subscribe!
Great Presentation , covers all the important points, many thanks
Thanks for your comment Sean. Appreciate it. Please do subscribe in case you haven't. Cheers!
Cleared my doubt.
Excellent video.
Thank you Saumyojit. I am glad you found it useful.
Please do subscribe to get notified when I upload related useful videos.
Commendable explanation..please upload more videos ...of business intelligence
Thank you Kajal. Please do Like, Share & Subscribe. I am working on content that includes end to end DWBI with real-world data. So stay tuned 😎
You saved me a lot of time man, thanks
Glad to hear that. Thanks!
Very well explained and all the details are clearly described. Subscribed😊
Thank you Sravanthi :)
Very well explained.. Good way of explaining as well.. Great video 👍
Thanks a lot 😊
Well understood. Thanks for the lecture
Without doubt, the best tutorial, even with my experience that was refreshing!
Thank You ! Please do subscribe.
Very nicely explained . Superbbb :)
Thank you Sunita :)
Nice explanation. Thank you, sir😊
Thanks a lot!! I'm not from science background, but still could understand clearly!!
Thank you Radhika. Happy to hear that comment :)
I am glad it helped. Please do subscribe !
Awesome 10 minutes 👍
Thanks finally an English titled video who is actually explained in English.. :) Very well
Thank you Mr. Tarik. Encouraging words like yours are worth the effort. Feel free to browse my channel, and do subscribe :)
Clear & Concise. Great job & TQ!!
Thank you. Please do subscribe for more such videos.
@@DataAcademyIN You already have a new subscriber & I will be back for more!
Great quick intro to the different levels. Thank you!
Thank you J !
This is really great for revision purposes 😅 short and to the point. 👍
Hello Muhammad. Glad you think so! :) Please do Like, Share & Subscribe !
You did a great job, your explanation is too good thank you!!
Thank you Mouni. Glad you found it helpful. Please do subscribe if you haven't already :)
very good and very well explained in clear english
Thanks Mohit. Please do subscribe to get notified of new videos.
Super helpful and clearly explained! 😊
Thank you Rowlands for your comments. Please do subscribe !
Thank you very much, this video really help my work
Thank you Muhammad Lucky Syahir. Please do subscribe !
Very nice explained 😌😌 thanks for this buddy.
Thank you 🙏 please do subscribe
Many thanks man
This helped me !
Thank you Mostafa !
does the sales table in this example have a primary key or not? It uses 3 foreign keys but they are above the line so am a little confused whats going on there.
Hello. Regarding your question.
Your observation is right. There are 3 foreign keys in the Sales table. They are 3 foreign keys, but at the same time, all 3 together are used as Primary Key as well. Your question is arising probably because, you assume that only one column is used as a Primary Key. But that would be incorrect. A Primary Key for a table can be a single column or a set of columns. In this example, a set of columns is used as the Primary Key, because that is what is used to uniquely identify a record in the Sales table. Hope this helps !
Thank you, this is a consize and easy to process introduction!
Thank you for your nice comments Nathan. Please do subscribe !
Do you have any video which explains conceptual model?
I have a question. In conceptual model, can two entities be associated with both direct and indirect relationship?
e.g. engineer inspects item. This inspection generates inspection report.
So entity 'engineer ' can have a relationship 'inspects' with entity 'item'. Also entity 'engineer 'can have a relation 'conducts' with entity 'item inspection'. Entity 'item' will have a relationship 'undergoes' with entity 'item inspection'.
Is it valid?
Hello Rupa. Apologies for the delay in responding.
To your question -
Q: Do you have any video which explains conceptual model?
A: No, I do not have any specific video just on the Conceptual Model. I will probably upload in the near future.
Q: In conceptual model, can two entities be associated with both direct and indirect relationship?
A: Yes, you can have a direct as well as a indirect relationship between entities, as long as it is meaningful for the person reviewing the model. Ideally it is the Business/End User who is reviewing the Conceptual Data Model. In case it makes the model complex or the direct/indirect relationship only exists as an implementation outcome (physical data model), then it is best to leave it out of the Conceptual Data Model.
Hope these answer your questions!
Easy to follow style of explaining. Thanks
Thanks Sarath!
Is it mandatory to use tools to create data models? Can't we do it manually without using any tools? Will it create a bad impression in the interview if I say I haven't used any DM tool? Thank you!
Hello Sneha. It is not mandatory to use a Data Modeling tool, but it is hard to ignore the benefits it brings. Regarding interview, even if you don't get a chance to use a Data modeling tool at work, you can always get some hands-on outside of work. Once you are confident, you could say that you have indeed used a data modeling tool. But remember that, a data modeling tool doesn't necessarily improve one's data modeling skills. It merely eases the overall modeling process. Hope this helps !
This is just brilliant, keep it up
Thank You :)
Sir do they different methods like updown and bottom down moddels use thease 3 steps of design(conceptual, logical , physical)please answer
Yes. The 3 phases explained here can be used in both Top-down as well as Bottom-Up approach
@@DataAcademyIN sir what about the centralized and de centralized aproach
I am not sure what you mean by centralized vs decentralized. Could you give an example?
@@DataAcademyIN oh its ok sir, can i also no is it ok if use the world design insted of model ex- conceptual database design , logical databas) design)
Yes, you may use the word "design"
It looks like I was learning different data modelling methodology 😃
1. logical model, called also Entity Relationship Diagram (ERD) represents entities and main relations between them, has usually primary keys and some main attributes as well, entity is drawn as a rectangle with rounded corners, and entity name is always singular, an entity is one instance of something,
2. physical model, called also as Data Diagram (DD) is generated from ERD also FK columns are added automatically, other columns can be added to the DD manually as well as other UK, indexes and partitions, entities are called tables, attributes are called columns, table is drawn as a rectangle with sharp corners, having a well designed DD we can generate table creation scripts so no manual work is required from developers, table name is always plural, a table is a collection of entities,
3. we should avoid adding a table name to table column names, table product should have columns description, name, short name, size... but not product_name, product_description, product_size...
"not product_name, product_description" - depends. If the target of the model is reporting, you would end up with 10 columns all called "name" which is confusing and you would spend ages renaming each column in the report. Much better to give them full names.
The other advantage of having the table name is if it is a foreign key, you can use the target table name (with role if needed) e.g. "Product_Id,Product_Code,ProductGroup_Id" or "Customer_Party_Id, SalesRep_Party_Id"
@@MrAndrewjdavis yes and no :-) if you want to distinguish columns from different tables, you can use table and column aliases, it takes a bit more work but it is better in my opinion, also a column name like "Product_Name" looks ugly on the report for end users, usually it will be renamed as "Name" or "Product name" on reports, not to mention that reports may be created in other languages, what people from English-speaking countries forget often, databases are usually built in English as they are often created by international teams, while reports are created in accordance with local requirements and often have to be created in the official language of a given country
Very good presentation and tips. Thanks for sharing this, it is very helpful indeed.
Many thanks Wilmer. Please do subscribe !
Really cool explanation!!!
Thank you Ami for you comments. Please do subscribe !
Thanks! Very helpful for a beginner :D
Thanks Roland !
Very clear, thank you
I am happy you found it helpful. Thank you for your comments. Please do subscribe !
Thank you sir. Very good explanation
Thank you Sankari. Please stay subscribed :)
Thanks very insightful
I am glad you found it useful. Please do subscribe to support my work🙏
Excellent, thank you
Glad you enjoyed it Vijayan. Please do Subscribe !
Great explanation!