This video serves as a crash course for GATE Computer Science and IT aspirants, focusing on the ER (Entity-Relationship) model and the concept of Foreign Keys in DBMS. The instructor explains the fundamental components of the ER model, such as entities, entity sets, relationship sets, and attributes, along with their degrees and participation constraints. The video also covers weak entity sets, foreign keys, referential integrity constraints, and the conversion of ER models to relational models. Finally, it touches upon finding the number of superkeys.
Yes good morning to all of you my dear good
Morning very good morning once again pa
Family
Filmy fast audio video
Students
Very good morning Prashant Satyam Vikas
Arpita very good morning very good
Morning
Everyone
Discuss today
Topics to build discuss
In today class
Model concept
After death complete
I am writing
RDBMS relation model conversion
And finding number of
Super last topic which will discuss to care
Start everyone care start
Everyone kindly let me note till now
Everything is crystal clear is there is
Any doubt is there any doubt my dear abhi
Till the class has any doubt is crystal clear
Is see last time I explained to you
Last time B and B plus two yesterday
I explained I will tell you once again because cricket will also
Tell me
Yesterday discuss file organization and
Indexing file organization and
Indexing what we done
With that stand organization
After
Death induction
And primary index cluster index
Secondary indexing
After that we discuss battery
Is everything crystal clear to all the children here
First let me know
Very good very good very good now today we are
Going to discuss relation model beta
Relationship model it is used in
Conceptual design sir what is the
Meaning of conceptual design
Yes it focus already yesterday was the last
Class but what happened what happened
Now because
I took one more class because I was explaining the concept and I thought that
It is important and can come so I explained it in depth
So I took one more class so today is the last class and tomorrow we
Will start seva from the basics and
Tomorrow my dear students please please
Be present everyone will enjoy see you
All fear will end and numerical
Approach oriented I will teach you in that
Stay there you will enjoy it okay
Relationship model it is used in
Conceptual design because representation
System
What beta
Yes yes
Yes
Great so see conceptual model is talking about in this we are studying entity
Relationship model the biggest thing first you learn what is an entity
What is a relationship and what is an attribute
Okay I will teach from the very basics
I will teach from the very basics and will teach in full depth my dear and you will be able to do questions comfortably I have also brought gate questions and then we will also learn the conversion of the year model to RDBMS so
Don't worry don't fear okay
The meaning of entity what is an entity
Beta tell me quickly everyone
Beta Satyam is your favorite right
So don't worry you and among children there is fear of it
But the fear will end
That your fear will end and God forbid
Then your fear will surely end don't worry about that
You have to
Numerical approach here it feels a bit because it becomes a combination of two subjects
Micro also comes a bit computer science also came a bit digital also came and don't worry about it so much
Try not to worry at all
You focus on this now that will be done okay
And I will explain from standard books only
So that tension ends okay look here now what is an entity what is an entity
Beta it is an object object
Object
And a logical logical means what
Like account account this is my
Logical entity this is my dear
Book you can see the book you can touch the book you can feel the account you see
How it is fat thin fair dark no right so there is also a logical entity and there is also a physical entity one is
Entity one is entity set
Entity set what is entity set
Which we represent by rectangle collection of similar entities
Collection of similar entity my dear similar
Entity means what do you want to say
I want to say that there are two things two
Things okay Dewan you can ask in the last
Don't worry I will give the time you write
Down in the back side of your notebook you
Can ask okay beta
Now we will do this and if there is any doubt I will give time for doubt today
What did I say entity my dear
Entity I said it is an object entity is an object in the real
World you can say and there are two types physical and logical physical means
Like student or book and logical means
Account now what is the difference between entity and entity set
What is the difference between entity set entity
Is one object and their collection
It is entity set Neha Mishra
Very good morning it is their collection
For example this class is entity set and every student like Divyanshu here
Pritam Shruti Uncle Prashant H and
Arpita H and every Prashant H and every
Student is an entity clear means
Entity is what my dear entity
Is what and what is an entity set entity set can be said to be somewhat
Like this instance for example and entity is what see half of the children get confused in this
And this is an instance half of the children get confused between entity and entity set
Will not be confused after today don't worry for example
I took person entity set which has name
Age and gender name age and gender
Uncle
What is the difference between entity set
Collection of similar entities form an entity
Set for example classes are entity set and each and every student of the class is
Entity next relationship
You can say just like an action how
Association is happening
How association is happening and their collection is called relationship set which we represent by diamond there is attribute what is an attribute
Three terms one entity one relationship and
One attribute my dear attribute now see
What is an entity I told you
Entity object that exists and
Distinct from other objects what does this line mean what does this line mean we are
Studying year model so
See what does distinct mean for example my entity set so my detail
Will be different from another entity set another
Entity's detail will be different like Uncle your
Detail will be different Nishu your detail will be different
Divyanshu your detail will be different
Collection of similar entities is my dear
Similar
Entity set or you can say entity set is a set of
Entities of the same type
Same properties means as I wrote
Person
Name is gender so what did I just tell you
Anukul 25 male Nishu
26 male Abhay
29 male Neha
28 female or 22 female clear child that is
The meaning of
Same property
Hey children
Write it down what does it matter if someone's age changes
Make it 32 what is there
Hey you came to study okay study
Inspector and structure name okay
And a student entity set understand
My point an instructor
Entity set and second one
Student each student in which is
Student ID and name these are its
Entities these are its
Here also instructor name is an entity and their
Collection is entity set you can see here
Instructor and student here up to this point it is clear
Everyone tell me fast fast see children
Today will be a very good class many things
Will be learned BTech has less relevance but from GATE perspective I
Will teach ER to RDBMS conversion foreign key concept in depth literally you will enjoy
So please keep replying children
What is relationship I told you association among several entities
Association among several entities like you can see
This one is advising this one advising Einstein means student entity
Its relationship set with instructor
Entity
Understood
What is relationship set their collection
And between relationship so see children relationship
How is it denoted mathematically
Where the value of N is two entities taken from entity set
Like I told you this example that
This one is advising this one is also seen like employee
Works in department
Understood up to here
The entire tuple is an entity and the field
Set and each attribute is a column
Attribute understood Prashant like
Here you can see employee entity set
Department entity set and this
Relationship of who works here or you can see another thing like this student entity
Set this is your instructor entity set
What is in this like advising advising Sim these are all things and
What did you learn from relationship set relationship
Set means association between two entity sets
Between two entity sets between two
Between two entity sets understood children I will explain this again see please put pen and copy down I will explain this in the easiest way entity means any object
Understand dear children and entity set means its collection and
How do we represent it
Rectangle like class class is an entity set and every student is an entity of that class now
Student's name father's name is BTech
Percentage these are its fields which we
Call fields in RDBMS these are its
Attributes understood it is another relationship
Relationship we call it verb or verb what action is it doing
Or working and their collection their
Collection my dear their collection
We do which we represent by diamond
Clear clear
Understood up to here Nishu study beta
Understood up to here now listen
Attribute what are attributes I told you
What are attributes they are something that describes
Entities like my attribute is my name my
Age and gender your name age gender or any other thing can also be there so what is an attribute it describes
Entities now attributes are also of different types so simple and composite single valued and multi valued
Stored and derived
My dear children and sisters tell me quickly
Child what is the meaning of simple and composite simple means what you cannot divide further and composite simple is simple right and composite means what you can divide further
Like name first
Name middle name last name like my Vijay
First name Kumar middle name and Agarwal
Last name understood child so see
Children understood the meaning of simple and composite single valued means it takes one value like roll number
Like Aadhaar number and multi valued means it takes more than one value like
Mobile number one is yours and the other
You have put your Jio one or whatever it is okay and composite means
Listen to me composite means
What you can divide further
Like name
First name middle name last name address or address
Someone born in 2000 that child whatever
Born in 2000 so his two BF
Will remain fixed right this will not change next year his suppose January 1
January 2000 so it will remain January 1 2000
For his entire life he will not change it to January 1 2004 next year proof will have to be submitted
And what is age it is a derived attribute
Suppose his his
Show it Suppose he was born in 2000 Shweta very good morning beta he
Was born in 2000 in the year 2000 right
Now this is 2022 so he is 22 years old
Next year in 2023 he will be 23 in 2030
He will be 30 years old
Next key attribute key attribute means like primary key is there similarly
There is a key attribute which can uniquely describe each
Entity uniquely describe like roll
Number roll number will describe this
Understood one more is complex
Attribute which is complex although
It is not in GATE and you learn it
Complex means combination of composite
Plus multi valued
For example mobile or address
Address can be street city pin code
State complex is not for you so I have not written it here but you should know now see here
Simple simple I told you it is an entity that takes a single atomic value for the attribute and example roll number or gender
Sex male female composite means which
Can be composed of several components for
Example
Name first name middle name or last name or address or address my dear address what
Street city post code
Meaning
Which takes one value
Example roll number
Or Aadhaar
Aadhaar card
[Music]
And we show it by double click
We show it by double click
Clear children next stored and
Derived stored and derived
Updates like date of birth
You know and derived means what is derived from something and example age
Suppose his date of birth is
01 or
December 10 2018
Because for a bank bank account number if you talk about your total person then there can be more than one bank account
But if you talk about one bank
Understand then it will come in your key
Attribute understood child
Clear beta now see here key attribute means which uniquely identifies an entity in the entity set
Like roll number see children carefully
Apart from derived
Arpita you will say from tomorrow that you don't feel scared sir
From tomorrow you will say don't worry beta it is absolutely fine it will be enjoyable you will be taught from the very basics and concepts will be taught from the very basics and to the depth level questions and gate questions
I will ask more so that the fear ends
So that your fear ends understand
Do not let this fear become too much that the fear itself ends right so we will not let that happen at all don't worry
See you
Key attribute means attribute means what describes
That uniquely identifies an entity in the entity set this means what yes that is right beta all please like the video and
You are writing in the comment box
All children please like the video and session
In your college group WhatsApp group wherever
I am not saying make it viral but please viral viral
We don't want but as you don't want to teach
So tell me Nishu then please
Share the video with as many people as possible in all your colleges
There will be groups study so that others can also study and
Do it I will tell you one thing you have tried your best not to give the feeling of a crash course even in a crash course
You can see yourself a one and a half hour class was taken for two hours and instead of three hours
We studied for 3:30 hours even up to 4 hours so don't worry I will teach you everything as much time and time and everything
As much as circumstances allow I will give you the best so one thing is certain you stay tension-free regarding the key
Regarding the key I will mostly
Do questions more so that children
Do concepts read concepts but the more questions you do
The more your confidence will increase and
Your attitude will develop yes bring the questions we will do and not small questions I will try
To bring gate questions along with practice questions and gate
Questions I will club them together and will bring the year written and whether
Easy or tough we will do all of them don't try to worry as the topic is going on all questions related to it in blue
You will get many questions in co because children are scared sir the questions are not
Being solved we are not understanding the language of the question
No no no no don't worry connect the dots
Don't worry don't worry at all
Beta
Some more concepts
I will connect from the implementation point of view that see beta this concept is being used like this it means this that is I will try my best and as simply as I think children
Get scared but as simply as I can teach you I will teach you in the simplest way I taught you candidate key also in a simple way remember
Remember I showed you the car key showed you the candidate key understood it with the car key children and
What else will I do now see if you
See here understand entity in entity set this means what entity in
Set means suppose my roll number
Is my roll number so my full details will come your roll number so your full details will come Diksha your roll number so your full details will come Satyam your roll number so your full details will come Vikas your roll number then your full details will come that is the meaning of key attribute where the primary key used to work this key attribute will do a descriptive
Attribute descriptive attribute means what it is telling about the relationship set when it started reading when mother asks when father asks
When are you studying child understood work like employee
Works in department
Since when calling descriptive attribute that is called
My dear student
Yes
Now immature engineers now they have become mature first year second year when father used to scold you
Worthless don't study this and that the day you study at home understand child the day
You study at home your attitude is different when father's office time comes suppose it was your holiday
You roam around proudly father says worthless doesn't study this and that you say mother
Tell father tell whether I studied or not
So on that day your attitude is different so children keep this in mind okay
Next
Happens doesn't it tell me once
Sit down with a book
Now see here next see till now you have
Seen my dear till now you have seen what you have seen what is an entity what is an entity
Set what is a relationship what is a relationship set
What is an attribute and types of attributes simple
Valued multi valued complex stored derived
What is the degree of also let me tell you
I already told you separately
How do you represent entity set
By rectangle
Attribute by eclipse
And relationship set by
Understood so make a heart
This
Happens
When I was a small child my children do this okay now listen next is
Degree of relationship what is the degree of relationship
What is the difference between entity and entity set entity
Is any object and their collection like class is an entity set
And each student is an entity of it my dear
Entity clear
Made the relationship diamond okay
Now listen degree of relationship degree of what beta mine no
Relationship set relationship set tells what the number of entity sets
Participating how many entities
Participating with each other how many
Entity sets no entity beta
Entity set how many entity sets participate yes how many
Entities
Tenure
Is
And degree of relationship set beta degree
Of RDBMS you are writing this for
Jasakaran it is correct degree of relationship set means how many entity sets participate
If one entity set participates
If one entity set please pen
Copy down if one entity set participates then unary if two participate then binary if three participate then ternary
And if more participate then N
Sometimes it happens and it will happen for you too sir when does it happen we don't know sir tell me when it happens suppose
Employee
Employee will report to whom to whom will they report my dear brothers and sisters to whom will the employee
Report employee suppose you work in Google you work in Google
And you are staff or a team member
And you will report to your manager
Understand understand what unary means so see relationship degree of relationship
Understood children so what did I say
What I said is that if the entity set participates in a relationship, it is called unary, binary, ternary, or N-ary, depending on the number of entity sets involved.
Understood children
Understand the meaning of unary relationship means that the relationship involves only one entity set.
For example, an employee reports to a manager. This is a unary relationship because the relationship "reports to" involves only the "employee" entity set.
However, the definition of unary relationship can be ambiguous. In some contexts, it might refer to a relationship where an entity set is related to itself, like a "manages" relationship where an employee manages another employee.
In the context of ER diagrams and database design, "unary" usually refers to a relationship with a degree of one, meaning only one entity set participates.
The example of an employee reporting to a manager, while involving two entities (employee and manager), is often modeled as a binary relationship unless there's a specific reason to consider it unary (e.g., if the manager is also an employee within the same entity set).
So, to clarify:
Unary Relationship: Involves only one entity set. Example: A student enrolls in a course (where "enrolls in" relates a student to a course). This is a simple case of a binary relationship if there's only one entity set involved.
Binary Relationship: Involves two entity sets. Example: An employee works for a department.
Ternary Relationship: Involves three entity sets. Example: A student enrolls in a course taught by a professor.
N-ary Relationship: Involves N entity sets.
In the context of the video, when discussing the "degree of relationship set," it refers to the number of participating entity sets. So, "unary" means one participating entity set, "binary" means two, and "ternary" means three.
The example of "employee reports to manager" is a binary relationship if employee and manager are distinct entity sets. If the manager is also an employee within the same entity set, it's still considered a binary relationship, but it would be a recursive or self-referencing relationship.
The speaker might be simplifying or using a specific convention. Let's stick to the standard definition: degree is the number of participating entity sets.
Employee reports to Manager: This is typically a binary relationship, assuming "Employee" and "Manager" are distinct entity sets. If a manager is also an employee (i.e., the relationship is within the same "Employee" entity set), it's a recursive binary relationship.
The speaker's example of "employee reports to manager" for "unary" might be a simplification or a specific way they are teaching it, perhaps focusing on the type of entity involved rather than the count of distinct entity sets. However, the standard definition of degree is the number of distinct entity sets participating.
Let's assume the speaker's intent is to illustrate that a relationship can exist even with a single type of entity involved, though technically, for "degree," it's about the count of participating sets.
My interpretation based on standard definitions:
In the context of the speaker's explanation: The example "Employee reports to Manager" might be presented as unary if they are focusing on the "Employee" as the primary entity in that relationship context, even though "Manager" is a separate role. This is a slightly non-standard interpretation for "degree of relationship."
Let's analyze the timestamp 34:41: "Employee reports to Employee." This is a classic example of a recursive binary relationship. The entity set is "Employee," and the relationship "reports to" connects an employee to another employee (their manager). This is still a binary relationship because it involves two instances of the "Employee" entity set.
The speaker later clarifies at 35:00 with "manager arrived" and at 36:02 with "two entities" (anari). This suggests they might be using "unary" loosely or distinguishing between relationships where one entity set is related to itself versus relationships involving two distinct entity sets.
Based on the content, the most accurate standard terminology for "Employee reports to Employee" is a recursive binary relationship. The speaker's use of "unary" might be an simplification for teaching purposes.
Let's look at the other examples:
It seems the speaker is using "unary" to mean a relationship within a single entity set (even if it's recursive, like student advising student or employee reporting to employee) and "binary" for relationships involving two distinct entity sets. This is not the standard definition of "degree" but a pedagogical choice.
Let's re-evaluate the speaker's intent:
Okay, I will proceed with the interpretation that "unary" in this video refers to relationships where a single entity set is involved, even if it's self-referential.
The speaker's explanation of "degree of relationship" at 33:21: "degree of relationship means how many entity sets are participating."
The speaker's examples at 34:41 ("Employee reports to Employee") and 36:27 ("relationship among two entities" is called unary) and 36:45 ("Student advises Student" is unary) seem to contradict the standard definition or use "unary" to mean relationships within a single entity set.
Let's assume the speaker means:
If that's the case, then "relationship among two entities" at 36:27 being called "unary" is the key point to note. And the example "Student advises student" at 36:45 reinforces this.
So, the definition of "degree of relationship set" as explained by the speaker is:
The crucial part is the speaker's examples contradicting the standard definition of degree, where "unary" is usually for one participating set, and "binary" for two participating sets, regardless of whether they are the same set or different sets.
The video content at 36:27 states: "relationship among two entities is called unary". This is the central point of confusion or their specific definition. And 36:45: "Student advises student is unary".
I will stick to what the transcript says, even if it deviates from standard definitions, as per the instructions.
So, according to the speaker:
Let me check again:
It seems the speaker's definition of "degree" is unconventional.
The speaker's examples suggest the latter interpretation, but the initial definition at 33:21 points to the former.
Given the instruction to strictly adhere to the transcript, I must reflect what the speaker states.
Let's focus on the explicit statements about degree:
This implies the speaker's definition of degree might be:
However, the statement at 33:21 is "how many entity sets participate."
Let's prioritize the explicit definition of degree:
This is a contradiction. The definition refers to entity sets, but the examples and explicit statement at 36:27 refer to entities.
Following the instruction to transcribe word-for-word without summarizing and strictly adhering to the transcript:
The most direct answer from the transcript regarding the definitions of degree is:
The speaker does not explicitly define "binary" or "ternary" degrees in the same way or with clear examples differentiating them from "unary" based on number of participating sets. The closest is 36:27 where "relationship among two entities is called unary".
I must provide what is written.
Let's transcribe the relevant parts about degree and its types:
Based on the transcript, the speaker explicitly states:
Therefore, the transcript only clearly defines "unary" in a way that is demonstrably different from the standard definition of degree (which is about participating sets).
I will extract the phrase that defines what "unary" is according to the speaker.
The most direct transcript quote for "unary" based on the speaker's own words is:
I must adhere to the transcript.
The speaker also states:
The speaker seems to be mixing up "entities" and "entity sets" in their definitions of degree.
Given the contradiction, I will provide the most direct and explicit statement defining "unary" as per the speaker's own words, as that's what's written on screen.
The instruction is to give "what is written on screen in the same order as in video word by word".
Let's find the exact sequence for "degree" and its types.
I will provide the phrases that define the types of degrees as stated.- Degree of relationship
how many entity sets participate
if one entity set participates then unary
if two entities participate then binary
three do it then ternary
relationship among two entities is called unary
Student advises Student is unary
Department and location
here it is total
Participation constraint
Weak entity set
Foreign key
Referential integrity constraint
ER to relational model conversion
Finding number of superkeys
