Database Design 33 - Cardinality
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- เผยแพร่เมื่อ 18 ก.ย. 2014
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thank you so much for this Caleb. Remote Learning with this courses has been a struggle and this video (and im sure more) saved me.
Perfect descriptions - really helped with my database homework
Thank YOU! You definitely explained it in a way I can understand!
This helped so much!! Thank you!
Love the chalkboard! Thanks for the video, very helpfull.
dude is so nerdy he uses old technology.
that... THAT is one savage nerd right dey :D
I didn't even noticed you stuttered! ;) Thanks for your clear explanation
king this was brilliant. This was so helpful!!! you didnt even stutter btw
better than my professor explaining for an entire week lol
same
Helped quite a bit, thanks
good video dude keep it up its not half as bad as you think
Thanks Caleb ,greetings from Galapagos, Ecuador
New Shirt, I love it! Live Free!!
So, in the logical schema, you don't include intermediary relations? And if that is the case, does that mean in the 'card_holder' to 'card' relationship we can also express a 'many-to-many'?
Thanks for the help friend, AIS is killing me
Thanks for clear and nice explanation
Thanks for sharing mate
Are there any java video lectures done by you?
Bro you tremendously helped me❤️❤️❤️❤️❤️🙏🏽🙏🏽🙏🏽🙏🏽🙏🏽, God bless you
Just wanted to add for those of you who are reading database systems: sixth edition Pearson as part of either a business analytics class or for data science. The book definition is speaking about the mathematical concept.
If you need understand the difference between the two and are still struggling head over to stack overflow and type in the book definition. Someone answered it already. It helped me.
Thank you!
In fact Mr. Caleb, when you get a credit card you get an account for that card. Modern accounting originated with the Knight Templar, and the purpose of the account is to allow multiple family members transact on or against the held money /goods.
Thank you so much
yoo catch you there man!!!
what about zero to many?
hey you should do a software engineering .. your great at explaining these things compared to some of my professors...
This is a part of software engineering. Software engineering is a huge topic...
yehhh and?
cheers pal. way more help than my lecturer tbh
haha unfortunately I know exactly what you mean
this man is a god at teaching
thanks bro
it's like watching matrix movie that had CRT embedded monitors as "advanced" technology... tech changed so much
Man, I wish you were my professor
great video
Sweet new AMERICA shirt!
You were great even in 2019.
2014*
2021 still his videos are relevant.
Watching this in 2022. U were so young then.
This is not Cardinality you have explained Relationships. Cardinality is the next step where you document the min and max number of entity occurrences associated with one occurrence of the related entity. Ex. (1,4) would be placed under your connectivity diagram on the many side an (0,1) on the one side.
sir this is what I want to know. can you tell me more? please.
Al Simmons, can you please elaborate on the difference between Relationships and Cardinality? Everything I have read suggests that Cardinality and table 'Relationships' are interchangeable and your comment makes them sound only tangentially different. Can you explain what you mean by 'Cardinality is the next step'? What is the first step - defining the relationship? Isn't the relationship implied by the Cardinality? Thanks!
Good thing i read the comments section.... smh
@Al Simmon, is your comment a valid feedback or just "boring philosophy" ??? you can at least answer people you confused.
It would be useful if people did elaborate on their comments.
My understanding of cardinality is new but is as follows - hopefully it'll help some people (though I'm still progressing my learning for DBA):
Things can have a high and low cardinality. Something like a boolean has a low cardinality as it has, not including null, 2 available options - true & false.
Something with a high cardinality has a large range of options and is, by rule of thumb, more unique. ID being a perfect example as it increments and has a unique value.
So a way you can use this to improve performance is by configuring an index to use the high cardinality value first and then use the low cardinality on the where clause.
Imagine a DB that contains video parts that are to be processed into one single video and the ones that have been processed. You have a script that every minute checks the DB and processes the videos that require it.
To improve the read of the data you could do:
CREATE INDEX ON tbl (id) WHERE media_processed = FALSE
This would allow the database to pull all of the unprocessed videos quicker than if for example you just did a select by the media_processed value as with that scenario every record would have to be checked for the true or false value.
Thnx
The sound of chalk on blackboard
Shaggy is that you?
Why does he sound like Greg from succession, LOL. Thanks for the video tho.
Omg this is 9 years ago!
I was going to ask if we could be friends you are really cute
God😎
I have a big crush on you.
high on weed
yooo
Thanks for your efforts and time. But thats not the right explaination.
thanks bro