Database Design 33 - Cardinality 

same

dude is so nerdy he uses old technology. that... THAT is one savage nerd right dey :D

This is a part of software engineering. Software engineering is a huge topic...

yehhh and?

haha unfortunately I know exactly what you mean

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.

2014*

2021 still his videos are relevant.