Keys in RDBMS

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Keys in RDBMS

Рет қаралды 310,752

Күн бұрын

DBMS: Keys in RDBMS
Topics discussed:
1. Explanation about the need for having keys in tables.
2. Various keys involved in DBMS.
3. Super key with example.
4. Candidate key with example.
5. Primary key with example.
6. Alternate key with example.
7. Unique key with example.
8. Foreign key with example.
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Music:
Axol x Alex Skrindo - You [NCS Release]
#DBMSByNeso #DBMS #KeysInDBMS

Пікірлер: 136

@anjaligupta7532 4 ай бұрын

1000 times better explanation than our college teachers.. 👍

@user-bk3zf5me7o 3 ай бұрын

Which university

@rajwindersinghlall1468 2 ай бұрын

True

@ragapriyakarthikeyan3139 11 ай бұрын

The session is too engaging ,Sir. Got cleared with all the concepts🙂.Thankyou sir

@Hey_Haroon Жыл бұрын

I m from non tech background and this topics comes in my Mba course and you explain it very smoothly. thank you !

@debasisnath9951 Жыл бұрын

from where are u pursuing mba? is it mba in IT?

@Hey_Haroon Жыл бұрын

@@debasisnath9951 yes, From GL Bajaj institute greater Noida

@kawizekambowa3488 3 ай бұрын

Clear explanation indeed .

@nurlanacc1623 14 күн бұрын

@@Hey_Haroon Email in alone is superkeu? Because it has null row

@user-rd8rs4xl7b 11 ай бұрын

Such a great teacher with clean and clear explanation! thank you!

@robertbehrens7026 Жыл бұрын

you explained it 10/10, thank you so much!

@danielsims5771 11 ай бұрын

Oh my goodness. You explained the complex Lecture to a lay_man's view. I subscribed right away. Sending love from Zambia

@mutalekapambwe6882 9 ай бұрын

🇿🇲🇿🇲🇿🇲🇿🇲🇿🇲

@exploreyourself6776 Жыл бұрын

Precise And to the point.Well done 👍

@rayaneziadeh1879 Жыл бұрын

thank you for speaking clearly, finally found a video in which i can understand what its said

@aakankshakhawase1860 29 күн бұрын

Thank you for the explanation. Your explanation really helped in clearing the concepts regarding the keys.👍Great work!

@m-47recordzz35 Жыл бұрын

Nicely explained , Thnxx alot 💙

@Torchbearer777 25 күн бұрын

Thank you for giving the knowledge about DBMS Keys ❤

@Cobenis_Kar Жыл бұрын

Beautifully explained, thank you!

@kawizekambowa3488 3 ай бұрын

It is not that difficult , it was just clarity i needed. Thank you

@user-uw6tl4oz5b 2 ай бұрын

1.75 X club

@gauravsrivastava17 2 ай бұрын

clears all the concept about keys

@tuikasrivastava1763 25 күн бұрын

seriously better than my professor!!!

@RenuSharma-iv7cs 4 ай бұрын

Very nicely explained

@samuelayine418 3 ай бұрын

Great teacher !!!

@abdullateefidris-jf3ub 9 ай бұрын

Well understood, Thanks❤

@kabir73722 3 ай бұрын

Thanks very clear explanation

@regilearn2138 Ай бұрын

Wow, appreciate you for this.

@user-de4im7hf8i 25 күн бұрын

Thanks for a lot

@user-bl1tm3su6c 3 ай бұрын

really! understood very clearly , mainly this session has been too engaging without lag.

@manasvikumarthakur5471 5 ай бұрын

Great Explaination Sir !!!!

@umaraju593 6 ай бұрын

very clear explanation. thank you

@umabharathyts1998 25 күн бұрын

Thanks !

@sanjeebamat4485 Жыл бұрын

Great lacture thank you for making such wonderful video .

@Saha121-h6y 6 ай бұрын

Fantastic... Teaching..Great Sir Thank you sir

@jesusbrideindeed1657 7 ай бұрын

You are a great teacher

@shresth_bhakta Жыл бұрын

Thanks NESO academy for this! Indeed and infromative video !

@modiallo968 5 ай бұрын

excellent work sir, thank you!

@KathirNatarajan-wk3nc 7 ай бұрын

Very very clear, really useful, wonderful explanation.great mentor u r sir, pls put more videos regarding dbms sir 🙏🙏🙏

@Abhishek-jh9lz 8 ай бұрын

100/10 ❤

@monicabhattacharya9029 Жыл бұрын

Thank you so much sir 😃😃👌

@mohitzen Жыл бұрын

Thank you sir 😊

@dawaphunsumlodey153 Жыл бұрын

Simple and effective explanation. Thank you

@RishtonKiBaatein Жыл бұрын

Thank you so much!

@tinkupavan565 5 ай бұрын

Super explanation 👌👌👌

@abizeta7507 10 ай бұрын

great teacher😊

@rocklee3254 Ай бұрын

one thing i would like to add is that... (name + phone) cannot be a candidate key because they can have null values and the primary motive of candidate key is to uniquely identify a tuple. (name + phone) cannot be a primary key as well because primary key can't have null values.

@funkiel-nowka Жыл бұрын

@nesoacademy, are you sure that (Name, Phone) can be super key and candidate key? In "super key" part you've mentioned that you can not force an employee to have a phone number, so it can be null. What if we have in DB three employees named John without assigned phone number? 🤔🤔🤔

@baranhamoglu4072 10 ай бұрын

we need an answer to this, @funkiel-nowka if you found out can you explaine to me aswell ?

@baranhamoglu4072 10 ай бұрын

@Neso Academy

@haneenbaghdadi5966 9 ай бұрын

Even (Name, email) can't be a superkey coz what if email is Also null and the name might have repeated too...

@gokulnaathb2627 5 ай бұрын

You're right! I have the same doubt. Most probably, that part of the explanation is wrong.

@Bharathsuru 11 ай бұрын

Nice explanation 💥💥💯

@rivaldondezwenayo4028 Жыл бұрын

thank you i learnt alot from your work 😃😃😃😃😃😃

@yusefiguess Ай бұрын

Thank you very much for the video. I have a question, why are we picking {Name, phone} and {email} as candidate keys instead of {Name, email} and {Phone}?

@A2Blearning1999 10 ай бұрын

Thank You

@ravindrathakur4563 Жыл бұрын

Thanks

@Amdebirhan_Abebe Жыл бұрын

Thank you !

@sachinragu1742 Жыл бұрын

If one name is repeated twice and both the rows have null as their phone number then how will {name, phone} be a super key?

@Kanna12377 Жыл бұрын

{name, phone} is not a key because u can't identify a unique tuple by using this in that condition

@anusuyag5183 Жыл бұрын

@@Kanna12377for the super key u said like we can use name, phone as key right … that eg is coming for all candidate key primary key and alternative key.. then how come u r saying it’s not a keys

@Raven812 Жыл бұрын

It is candidate key

@ritasen225 Жыл бұрын

First you should make name and phone number as a key because it's not null but it's not not unique also

@queenkhan500 Жыл бұрын

Am also confused😢

@zeeleditz01 5 ай бұрын

Thankyou sir ✨

@yoyo-hm2qo 5 ай бұрын

wonderful！！thanks，i understand it 100%😂

@samsonsumba7875 2 ай бұрын

Great

@gokulnaathb2627 5 ай бұрын

Thank you

@tricks_without_treat Жыл бұрын

Thanks bro

@adriand.2884 Жыл бұрын

Where is the tutorial of Normalization? I need it right now hehe, were done at keys in rdbms

@jovankumar7780 Жыл бұрын

Thankyou sir ❤❤❤❤😊😊😊

@statuslover4867 Жыл бұрын

Thank you sir for nice explanation ❤️

@giack6235 4 ай бұрын

Thank you for the very clear explanation. Just a question: at 11:50 you are considering among candidate keys also {Name, Phone} but according to definition, candidate key is a minimal set of attributes to be key. Since we have already considered {ID} and {SSN} as keys, minimal set of attributes to be key is 1, while in the case {Name, Phone} set of attribute is 2, which is greater. So why do we consider {Name, Phone} still as candidate key?

@sumanthkumar4035 4 ай бұрын

"minimal set of attributes" it implies that if you remove an attribute from it, it's no longer a key. minimal doesn't mean number of attributes, implies no extra attributes

@kousik8042 Жыл бұрын

super key is like super set.but actually it is power set of keys

@hscodingdairies14 10 ай бұрын

Can someone please explain what is a unique key because it seemed same as alternate keys

@GIGAlex6 3 ай бұрын

Composite key at 19:28

@gottipadthasahithisahithig1137 3 ай бұрын

Sir could you post SQL tutorial

@sonuudarokar09 Жыл бұрын

You can add one thing here that is unique key allow only one null value....not more than one

@SatyamMaurya.. 5 ай бұрын

12:41 here , (salary and phone) too.

@DaiMoscv Жыл бұрын

(Name, email) what if the email is Null but the name alone cannot identify uniquely a tuple? In my opinion in this case it cannot be a superkey

@haneenbaghdadi5966 9 ай бұрын

Yess....even (Name, phone) can't be a super key...the phone no. Can also be null and the name can be repeated too...ig we hv to assign these attributes with certain keys separately....

@kavinarasan2619 Жыл бұрын

nandri thale

@varanaze. 11 ай бұрын

😂😂 Mass bro nee 😂

@nurlanacc1623 14 күн бұрын

Email in alone is superkeu? Because it has null row

@Getagrip8 Ай бұрын

In a candidate key what if one attribute values are not unique and other attributecan have a null value, How can we identify it...For example there are 3 john in the table and if two have no phone numbers then how can we identify the specific tuple

@sumanthkumar4035 4 ай бұрын

So, the unique key, must support null values apart from being unique ?

@utsabbanerjee2770 8 ай бұрын

Lecturer key loves names like yusuf, alya, John , Robin etc.

@syedidrees7354 Ай бұрын

how name and phone can be super key if there are 2 employees with same name and having null in their phone number field.

@somendrasarkar7837 9 ай бұрын

Let's assume a airplane reservation system. What can be a primary key? Flight Number or Flight Number+Date

@Hahe2023 7 ай бұрын

I think both can act as a primary key but according to lecture " primary key should never and rarely be changed " 15:55 So there may be chance of date not mentioned (null) so flight number will definitely be a primary key.

@shrutiagnihotri526 3 ай бұрын

If a column does not uniquely identify a tuple..it can't be a key...then how can u say email I'd can be a super key while it can contain null value

@aswin5226 9 ай бұрын

Is it possible for a unique and composite key to be something other than a candidate key?

@ishalkumar9037 Жыл бұрын

Which one was the foreign key ??? Dept. Code or any other ??

@mjordan1117 Жыл бұрын

why is salary on the table if you dont make use of it? Why is it not an alternate key?

@utube_int2075 Жыл бұрын

So, super key is set of all possible combinations of attributes that can uniquely identify tuples. Is it right?

@DnyaneshwarPanchaldsp 5 ай бұрын

🎉🎉

@Ganeshay-996 7 ай бұрын

Primary key --> PK PK is unique, NOT NULL, required , never duplicate and used for uniquely identify the data in table. every table have a max 1 PK. create table empinfo( id number primary key, ename varchar2(20), deptid number ); Unique key --> UK UK is unique, required, never duplicate and used for uniquely identify the data in table. table can have more than 1 unique key. UK allows null. every null is unique, we can not compare null to another null. thats why UK allows null, because it treats every null as unique. 10+null = null 10- null = null null is unknown and undefined, we do not know the value, so it always gives us null

@anusuyag5183 Жыл бұрын

Unique key can b id or ssn right.. how come name, phone will be unique key

@enisozturk8075 Жыл бұрын

I have the same question how the phone number can be a unique key? There could be multiple nulls.

@nashin0ki927 11 ай бұрын

8:16

@gokulanvs 3 ай бұрын

In the super key what if two employees having same name both don't have phone number , how will you uniquely edit their data

@AlphaNOVA69 Ай бұрын

Then it is not a super key, a super key should have attributes that are uniquely identifiable for each entry

@hosseinramezani5025 6 ай бұрын

l think Name and Phone togather cant be a super key, cause we can have two Johns that dont have phone numbers! please correct me if im wrong

@hewansolomon1973 5 ай бұрын

phone no is unique also it is can be null so it is super key i think

@gokulnaathb2627 5 ай бұрын

How can {Name, Phone} uniquely identify a tuple? Phone is nullable, right?

@moatemsulongchar8418 4 ай бұрын

I think we can set it to NOT NULL

@shivamtiwari9040 Жыл бұрын

at 19:19 name is not a unique key phone is a unique key and you are saying that set of name and phone is unique key, what if two employee of same name don't have phone number.

@kousik8042 Жыл бұрын

only phone number is also not a key. multiple employee might have no phone....2ndnot- employees with same name might also have no phone. so 'only name', 'only phone number', 'both name and phone number' are not keys...forget which type...those are not key first

@skyskitchen7872 5 ай бұрын

salary also can't be a superkey, right?

@C4_NETIC 5 ай бұрын

Yupp

@vaalarivan_p Жыл бұрын

yramirp yek dne: 14:32

@yoga_with_atharva 4 ай бұрын

why email is not unique key> as it is unique and null value

@poulomisantra2184 3 ай бұрын

some companies allow employees to have multiple email addresses, or they might have an email alias system where multiple employees share the same email domain. Additionally, allowing null values means that not all employees are required to have an email address, which further complicates setting it as a unique key.

@steveboel12 5 ай бұрын

How can the set {Name, Phone} be a super key if multiple people can have the same name and not every person has a phone number?

@Debugger_97 4 ай бұрын

Super key is possible of all combinations even null attributes can be used

@Debugger_97 4 ай бұрын

Phone number alone and with others can be made super key but name won't !

@Debugger_97 4 ай бұрын

Ask ChatGpt after providing some attributes to it

@lakshminarayanachintaginja1841 7 ай бұрын

Evatiki keys chepdam Saritha radhu ra😂😂😂😂😂

@hehehe9925 Жыл бұрын

can a candidate key have null values?pls anyone reply

@haneenbaghdadi5966 9 ай бұрын

Yess...Candidate key attribute can contain null values. Also know that it does not allow the same value in the attribute field.

@Tarakhan05 Жыл бұрын

12:28

@obito3248 11 ай бұрын

bro in 12:42 {name,email } will come or not ?

@haneenbaghdadi5966 9 ай бұрын

No...becoz name attribute has already appeared ...in {Name, phone} so u can't have repeated attributes in candidate keys... same goes for email...see this part again 12:17 ...as u can see the email has also appeared once{Email} so u can't hv it again.