Hello Subscribers! A lot of you had complained about the poor audio quality in this clip. So I am re-uploading this video with enhance audio. Watch it here - th-cam.com/video/cY7WZYhyC3o/w-d-xo.html
Hello Nico. I understand the confusion. Data Model and Data Schema sound very similar, or they are seem interchangeable. For the sake of clarity, I would explain "Data Model as a pictorial representation of the different Database tables and their relationship". This pictorial representation may not contain some advanced database objects such as Stored Procedures, Indexes, functions, triggers etc. Whereas "Data Schema is the actual collection of database objects that includes tables, views, stored procedures, indexes etc. A schema is usually represented by a bunch of .SQL files that contain the script." To summarize, Data Model is mostly a pictorial representation, whereas Data Schema or Schema is the actual script used to implement the physical database. Be aware that some people/organizations tend to mix these above definitions.
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.
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 --> th-cam.com/video/cY7WZYhyC3o/w-d-xo.html Please do subscribe in case you haven't. Thanks !
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 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
Sir, Please make a video to describe about database. Where student don't want to learn any of database technologies like My SQL, Oracle, MongoDB, Hadoop, Google's or Amazon's Cloud Databases and so on. Please make a video where students want to learn in detail about. 1. Concepts. 2. Terminologies. 3. Types of databases (Relational, Non Relational, SQL, NoSQL etc.). 4. Data types supported by various database technologies. 5. Compatibility of different database technologies with different mainstream programming languages (Like Python, Java, PHP etc.) for developing backend of web applications. 6. Working of different types of database technologies. 7. How to calculate resources required. 8. How to calculate costs for different types of database technologies for the given requirement.
Hi Virendra, That seems like a huge ask :) I doubt if I can fit in all of these advanced topics into my videos. I plan my videos on abstract & high-level concepts. But I will keep these on my to-do. I will see what I can do.
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.
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
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.
@@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.
There can be datatypes used in logical model too! And deffreance betwene logical and physcal model its just that physcal name of atributes are just more relateble to names that we will use in our DATABASE...
I agree with you that this is allowed, but I feel that it defeats the purpose of a Logical schema. A Logical schema should NOT be specific to a database. Hence, if we were to mention the Datatype, it should be a generic datatype. For example - A datatype of STRING maybe used in Logical schema, whereas in the Physical schema, this may map to either a VARCHAR or TEXT datatype (PostgreSQL Datatypes).
Hello Vladislav. Thanks for your comments. I am happy you found it good. Please browse my channel for more such videos. Do subscribe to get notified of new uploads. Cheers !
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Hello Subscribers! A lot of you had complained about the poor audio quality in this clip.
So I am re-uploading this video with enhance audio. Watch it here - th-cam.com/video/cY7WZYhyC3o/w-d-xo.html
how are data models different from data schema or are they the same thing
Hello Nico. I understand the confusion. Data Model and Data Schema sound very similar, or they are seem interchangeable.
For the sake of clarity, I would explain "Data Model as a pictorial representation of the different Database tables and their relationship". This pictorial representation may not contain some advanced database objects such as Stored Procedures, Indexes, functions, triggers etc.
Whereas "Data Schema is the actual collection of database objects that includes tables, views, stored procedures, indexes etc. A schema is usually represented by a bunch of .SQL files that contain the script."
To summarize, Data Model is mostly a pictorial representation, whereas Data Schema or Schema is the actual script used to implement the physical database. Be aware that some people/organizations tend to mix these above definitions.
@@DataAcademyIN thank you
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!!!
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.
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. 👍
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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 !
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 :)
Big Thank you Sir for such wonderful explaination!!!
Waiting for more video with some business cases
Very helpful. Clearly defined each and every models !!!
Thank You Nikunj !
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 !
Wow, great video. I tried to read about data models and was 100% lost. Now I 100% understand after watching this video.
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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 !
best video available on youtube for understanding Data modeling.
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 --> th-cam.com/video/cY7WZYhyC3o/w-d-xo.html
Please do subscribe in case you haven't. Thanks !
Great and simple explanation sir. It saves lot of time from reading theory sometimes
Thank you for such a clear and accurate explanation of the different database modeling stages
Many thanks Julio. Please stay subscribed to support !
Great quick intro to the different levels. Thank you!
Thank you J !
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 !
This is actually really good explanation.
Thanks Gunjan !
Just a great video for beginner who want to understand the data model. Thanks for such short but very useful concepts
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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
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Very simple video, but extremely clear: it helped a lot before digging into more detailed tutorials. Great work indeed.
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@@DataAcademyIN : Of course !
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 !
Thank you, this is a consize and easy to process introduction!
Thank you for your nice comments Nathan. Please do subscribe !
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!
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Thank you so much for such a wonderful explanation…. Brief and crisp!
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Very helpful and informative, Please keep educating people. God Bless.
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Nice explanation. Thank you, sir😊
Just what I was looking for. Excellent tutorial!
Thanks Aqib !
Very helpful, clear and detailed! Thanks a lot.
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Hands down the best Video out there.
Much thanks SaiKiran :)
Best explanation for these 3 models
Well understood. Thanks for the lecture
Very good presentation and tips. Thanks for sharing this, it is very helpful indeed.
Many thanks Wilmer. Please do subscribe !
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 !
Great Presentation , covers all the important points, many thanks
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Best explanation I’ve ever seen for DBMS
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Sir,
Please make a video to describe about database. Where student don't want to learn any of database technologies like My SQL, Oracle, MongoDB, Hadoop, Google's or Amazon's Cloud Databases and so on.
Please make a video where students want to learn in detail about.
1. Concepts.
2. Terminologies.
3. Types of databases (Relational, Non Relational, SQL, NoSQL etc.).
4. Data types supported by various database technologies.
5. Compatibility of different database technologies with different mainstream programming languages (Like Python, Java, PHP etc.) for developing backend of web applications.
6. Working of different types of database technologies.
7. How to calculate resources required.
8. How to calculate costs for different types of database technologies for the given requirement.
Hi Virendra,
That seems like a huge ask :) I doubt if I can fit in all of these advanced topics into my videos.
I plan my videos on abstract & high-level concepts. But I will keep these on my to-do. I will see what I can do.
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
Excellent explanation, very easy to understand. Thank You.
Thank you for your comments. Do subscribe to get notified of new uploads.
Very useful video. Thanks for your efforts in sharing this knowledge.
Thanks for your comments Ravi :) Please do subscribe for supporting more such content !
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 :)
thanks because it brings clear description from start to end.
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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.
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
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.
Simply the BEST. Thank you!
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Simple and clear. Thank you!
Than You Ilona !
This explanation is the best. so easy to comprehend...kudos
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This is really great for revision purposes 😅 short and to the point. 👍
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Awesome 10 minutes 👍
very simply explained and easy to understand. Thanks !!
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Your teaching is clearer than my lecturer , thanks alot man
Glad to hear that
I appreciate your efforts to prepare such a wonderful video!
Thank you for your encouraging comments.
Thank you for this great explanation!
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Wonderfull explanation Sir. Thank you very much for making the video.
Thank you for your comments Sudarshan !
Absolutely brilliant video. Thank you sir! 🙏
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thnx vry much u explained it all well
Thank you Ezra !
you explained it in a great and plain way. Thanks.
You're very welcome!
This was very detailed yet very simple explanation. Thanks a lot Sir.
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Great explanation, thank you very much.
Thanks for the encouragement Vildan ateş
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 😊
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 :)
This 13 min video explains one hour lecture. Thank you
:) Thank you for your sincere comments !
very helpul and conceptual video. Thanks a lot buddy.
Thank you Asad !
Really good one for beginners to understand easily
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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 !
Thank you the explanation is good enough and clear.
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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
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@@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
Awesome video. Very Explanatory.
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Nicely Explained! Thanks a lot!
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Very helpful and appreciated !!!
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this is the best explanation ever. You solve my problem
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Thank you very much! It's very useful :)
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Clear & Concise. Great job & TQ!!
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@@DataAcademyIN You already have a new subscriber & I will be back for more!
It helped me a lot! Thanks!
I am glad you found it useful. Thanks Ricardo!
very good and very well explained in clear english
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Commendable explanation..please upload more videos ...of business intelligence
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Very clear explanation of the topic...really appreciate it.
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Cleared my doubt.
Excellent video.
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excellent video! thank you very much!
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Very well explained, thank you so much!!
Thank You !
Will you do more videos?
Absolutely Yes. More videos in the making. Stay tuned to my channel !
Thank you very much, this video really help my work
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Very nicely explained . Superbbb :)
Thank you Sunita :)
You saved me a lot of time man, thanks
Glad to hear that. Thanks!
Very nice explained 😌😌 thanks for this buddy.
Thank you 🙏 please do subscribe
nice video very clear... thanks
Thank You Gokul !
you killed the game, my friend!
There can be datatypes used in logical model too!
And deffreance betwene logical and physcal model its just that physcal name of atributes are just more relateble to names that we will use in our DATABASE...
I agree with you that this is allowed, but I feel that it defeats the purpose of a Logical schema.
A Logical schema should NOT be specific to a database. Hence, if we were to mention the Datatype, it should be a generic datatype. For example - A datatype of STRING maybe used in Logical schema, whereas in the Physical schema, this may map to either a VARCHAR or TEXT datatype (PostgreSQL Datatypes).
Insightful ❤
Good video. Thanks :)
This is just brilliant, keep it up
Thank You :)
Very good tutorial. Thank you
Hello Vladislav. Thanks for your comments. I am happy you found it good.
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Thanks! Very helpful for a beginner :D
Thanks Roland !
such a clear description, thanks
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Without doubt, the best tutorial, even with my experience that was refreshing!
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simple explanation....thank you
Thanks Yadnesh !
Thank you so much. This was very helpful.
Glad it was helpful!
my lecturer spent half an hour on it and still couldn't explain it properly...not all scholars make good teachers
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@@DataAcademyIN already subscribed