I’m a tech interested guy. I’ve touched SQL once or twice, but wasn’t able to really make sense of it. That combined with not having a practical use leaves SQL as largely a black box in my mind (though I am somewhat familiar with technical concepts in databasing).
With that, I keep seeing [pic related] as proof that Elon Musk doesn’t understand SQL.
Can someone give me a technical explanation for how one would come to that conclusion? I’d love if you could pass technical documentation for that.
The statement “this [guy] thinks the government uses SQL” demonstrates a complete and total lack of knowledge as to what SQL even is. Every government on the planet makes extensive and well documented use of it.
The initial statement I believe is down to a combination of the above and also the lack of domain knowledge around social security. The primary key on the social security table would be a composite key of both the SSN and a date of birth—duplicates are expected of just parts of the key.
If he knew the domain, he would know this isn’t an issue. If he knew the technology he would be able to see the constraint and following investigation, reach the conclusion that it’s not an issue.
The man continues to be a malignant moron
Since SSNs are never reused, what would be the purpose of using the SSN and birth date together as part of the primary key? I guess it is the one thing that isn’t supposed to ever change (barring a clerical error) so I could see that as a good second piece of information, just not sure what it would be adding.
Note: if duplicate SSNs are accidentally issued my understanding is that they issue a new one to one of the people and I don’t know how to find the start of the thread on twitter since I only use it when I accidentally click on a link to it.
https://www.ssa.gov/history/hfaq.html
My guess would be around your note. If someone mistakenly has two SSNs (due to fraud, error, or name changes), combining DOB helps detect inconsistencies.
Some other possibilities, and I’m just throwing out ideas at this point:
Take this with a grain of salt as I’m not a dev, but do work on CMS reporting for a health information tech company. Depending on how the database is designed an SSN could appear in multiple tables.
In my experience reduplication happens as part of generating a report so that all relevant data related to a key and scope of the report can be gathered from the various tables.
A given SSN appearing in multiple tables actually makes sense. To someone not familiar with SQL (i.e. at about my level of understanding), I could see that being misinterpreted as having multiple SSN repeated “in the database”.
Of all the comments ao far, I find yours the most compelling.
Theoretically, yeah, that’s one solution. The more reasonable thing to do would be to use the foreign key though. So, for example:
SSN_Table
ID | SSN | Other info
Other_Table
ID | SSN_ID | Other info
When you want to connect them to have both sets of info, it’d be the following:
SELECT * FROM SSN_Table JOIN Other_Table ON SSN_Table.ID = Other_Table.SSN_ID
EDIT: Oh, just to clear up any confusion, the SSN_ID in this simple example is not the SSN itself. To access that in this example query, it’d by SSN_Table.SSN
This is true, but there are many instances where denormalization makes sense and is frequently used.
A common example is a table that is frequently read. Instead of going to the “central” table the data is denormalized for faster access. This is completely standard practice for every large system.
There’s nothing inherently wrong with it, but it can be easily misused. With SSN, I’d think the most stupid thing to do is to use it as the primary key. The second one would be to ignore the security risks that are ingrained in an SSN. The federal government, being large as it is, I’m sure has instances of both, however since Musky is using his possy of young, arrogant brogrammers, I’m positively certain they’re completely ignoring the security aspect.
Yeah, no one appreciates security.
I probably overused that saying to explain it: ‘if theres no break ins, why do we pay for security? Oh, there was a break in - what do we even pay security for?’
To be a bit more generic here, when you’re at government scale you’re generally deep in trade-off territory. Time and space are frequently opposed values and you have to choose which one is most important, and consider the expenses of both.
E.g. caching is duplicating data to save time. Without it we’d have lower storage costs, but longer wait times and more network traffic.
Yeah, I work daily with a database with a very important non-ID field that is denormalized throughout most of the database. It’s not a common design pattern, but it is done from time to time.
Yeah, databases are complicated and make my head hurt. Glancing through resources from other comments, I’m realizing I know next to nothing about database optimization. Like, my gut reaction to your comment is that it seems like unnecessary overhead to have that data across two tables - but if one sub-dept didn’t need access to the raw SSN, but did need access to less personal data, j could see those stored in separate tables.
But anyway, you’re helping clear things up for me. I really appreciate the pseudo code level example.
It’s necessary to split it out into different tables if you have a one-to-many relationship. Let’s say you have a list of driver licenses the person has had over the years, for example. Then you’d need the second table. So something like this:
SSN_Table
ID | SSN | Other info
Driver_License_Table
ID | SSN_ID | Issue_Date | Expiry_Date | Other_Info
Then you could do something like pull up a person’s latest driver’s license, or list all the ones they had, or pull up the SSN associated with that license.
The SSN is likely to appear in multiple tables, because they will reference a central table that ties it all together. This central table will likely only contain the SSN, the birth date (from what others have been saying), as well as potentially first and last name. In this table, the entries have to be unique.
But then you might have another table, like a table listing all the physical exams, which has the SSN to be able to link it to the person’s name, but ultimately just adds more information to this one person. It does not duplicate the SSN in a way that would be bad.
It is common for long lived databases with a rotating cast of devs to use different formats in different tables as well! One might have it as a string, one might have it as a number, and the other might have it with hyphens in the same database.
Hell, I work in a state agency and one of our older databases has a dozen tables with databases.
The main reason for the discrepancy is not looking at what was used before or not understanding that they can always change the formatting when displayed so they don’t need to include the parenthesis or hyphens in the database itself.
Okay but if that happens, musk is right that that’s a bit of a denormalization issue that mayne needs resolving.
SSNs should be stored as strings without any hyphen or additional markup, nothing else.
It’s more likely though it’s just a composite key…
This is not what he is actively doing though. He isn’t trying to improve databases.
He is tearing down entire departments and agencies and using shit like this to justify it.
Sure but my point is, if it was the scenario you described, then Elon would be talking about the right kind of denormalization problem.
Denormalization due to multiple different tables storing their own copies of the same data, in different formats worse yet, would actually be the kind of problem he’s tweeting about.
As opposed to a composite key on one table which means him being an ultracrepidarian, as usual.
Musk canceled the support for the long running Common Education Data Standards (CEDS) which is an initiative to promote better database standards and normalization for the states to address this kind of thing.
It does not fucking matter if he is technically correct about one tiny detail because he is only using to to destroy, not to improve efficiency.
I mean it matters here, as it’s literally the topic being actively discussed by the person who literally asked, so obviously it matters to them lol
Beat me to asking this follow up, though you linking additional resources is probably more effort that I would have done. Thanks for that!