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SQL vs. NoSQL Databases: What’s the Difference?

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Re: SQL vs. NoSQL Databases: What’s the Difference?

#31

Post by BinaryIdiot »

Many databases considered NoSQL actually have SQL now. Cassandra for instance. Granted it's not as critical to the execution as SQL is for RDMS but I would much prefer the distinction to be: RDMS / Relational versus KeyValue / Document Stores. But I digress.

Some of the other criticisms in this thread are very valid especially in the area of why you should use one versus the other so I won't bother regurgitate them I just felt like a better distinction could have been used between what they were comparing.

Re: SQL vs. NoSQL Databases: What’s the Difference?

#32

Post by hire_charts »

wvenable wrote: post #27
callesgg wrote: post #22

The article read like it is written by someone who has never understood how to use a SQL database. To quote Mr Torvalds himself: "Bad programmers worry about the code. Good programmers worry about data structures and their relationships." Something that i struggled with before i learned how to use a SQL/relational database was to actualy use the database relations in my code. I first specified the relations in the da…

In my experience, if you have the relational database model fully defined and correct then the rest of the application is pretty much designed. All the screens and elements you need are obvious.

This matches my experience. That's not to say that your application doesn't need to do any work on top of the data. Sometimes you need to interpret the data in different ways for different use cases, and often that means applying transformations at the application layer. But if you find yourself fighting against your own data model, it might be time to consider restructuring the data to better support your use cases.

Re: SQL vs. NoSQL Databases: What’s the Difference?

#33

Post by gshulegaard »

aristus wrote: post #18

Bah. People keep confusing the syntax with the data model. SQL is simply a notation to express theorems in relational set theory. It's pretty much the only pure-functional, side-effect-free programming language that's actually gone mainstream [0]. If you look carefully at the APIs of the "No SQL" databases, you'll find them introducing relational set theoretic features. To paraphrase Paul Graham's unbearably smug com…

This is interesting, but I admit I am a bit confused.

Having read "An Introduction to Database Systems" by C.J. Date (http://www.amazon.com/Introduction-Database-Systems-8th/dp/0...), I have a tremendous appreciation for Relational Algebra and Theory which allows for the closed functional nature/syntax of SQL which holds true across the various normal forms (1st-5th).

Perhaps due to my own lack of understanding, I always assumed that without an underlaying relational model SQL loses its closure. So for me, I always thought the distinction between SQL and NoSQL was whether or not the underlying database model was relational.

Sure for many of the queries against a non-relational model you could adopt a SQL-like syntax (which many languages seek to do), but it would no longer be operating in the closed Relational Algebra space.

Could you comment on this and help me understand the finer points/where I went wrong?

Re: SQL vs. NoSQL Databases: What’s the Difference?

#34

Post by zer00eyz »

manigandham wrote: post #29

Why is this even on HN? There's no reason to debate this, it's a content marketing fluff piece for a company that has no technical pedigree, written by a freelance copywriter rather than an engineer. It's also about 50% wrong. Let's just move on.

On some level I'm glad it is:

Things your boss or client will read, quickly turn into things your boss or client will say. I would rather be prepared for the wacky misinformed conversation that will happen, it helps keep down the laughter and frustration.

Re: SQL vs. NoSQL Databases: What’s the Difference?

#36

Post by gjolund »

paulmd wrote: post #30
Scarbutt wrote: post #26

Earlier quoted context omitted.

SQL migrations may seem tedious, but the process of planning your data model and having rigid definitions for your data types saves you huge amounts of time in the long run. Your reasoning seems too black and white, most the of the time, you can't know your data model ahead of time, that's why prototypes are so useful, so just using your language data structures or some less rigid datastore lets you get quicker to yo…

Having rigid definitions for data types doesn't necessarily mean the datastore is rigid. It just means that you know what type of data goes in each column. Like it or not, if you change your schema that change has to be handled somewhere - either you update the old data to the new schema (do this), or you handle old versions of the schema in the application (fundamentally non-scalable IMO). It doesn't matter whether…

I also really like the sqitch project for migration management.

http://sqitch.org/

Re: SQL vs. NoSQL Databases: What’s the Difference?

#37

Post by beachy »

zer00eyz wrote: post #34
manigandham wrote: post #29

Why is this even on HN? There's no reason to debate this, it's a content marketing fluff piece for a company that has no technical pedigree, written by a freelance copywriter rather than an engineer. It's also about 50% wrong. Let's just move on.

On some level I'm glad it is: Things your boss or client will read, quickly turn into things your boss or client will say. I would rather be prepared for the wacky misinformed conversation that will happen, it helps keep down the laughter and frustration.

And on that theme, then get ready for when your boss gets to the part about how NoSQL gives you:

"Rapid development. If you’re developing within two-week Agile sprints, cranking out quick iterations, or needing to make frequent updates to the data structure without a lot of downtime between versions, a relational database will slow you down."

Reminds me of this classic https://www.youtube.com/watch?v=b2F-DItXtZs

Re: SQL vs. NoSQL Databases: What’s the Difference?

#38

Post by beachy »

wvenable wrote: post #27
callesgg wrote: post #22

The article read like it is written by someone who has never understood how to use a SQL database. To quote Mr Torvalds himself: "Bad programmers worry about the code. Good programmers worry about data structures and their relationships." Something that i struggled with before i learned how to use a SQL/relational database was to actualy use the database relations in my code. I first specified the relations in the da…

In my experience, if you have the relational database model fully defined and correct then the rest of the application is pretty much designed. All the screens and elements you need are obvious.

Indeed, but if you are building in microservices, a new level is introduced.

If you can get your service boundaries and APIs fully defined and correct, then the relational database models (underpinning each of those services) just fall from the tree for you.

And then as you say the screens and elements are obvious.

Re: SQL vs. NoSQL Databases: What’s the Difference?

#39

Post by wvenable »

lanna wrote: post #23
aristus wrote: post #18

Bah. People keep confusing the syntax with the data model. SQL is simply a notation to express theorems in relational set theory. It's pretty much the only pure-functional, side-effect-free programming language that's actually gone mainstream [0]. If you look carefully at the APIs of the "No SQL" databases, you'll find them introducing relational set theoretic features. To paraphrase Paul Graham's unbearably smug com…

> side-effect-free How is SQL side-effect-free if it has INSERT, UPDATE, DELETE?

Those aren't side-effects, they are the main effects.

Re: SQL vs. NoSQL Databases: What’s the Difference?

#40

Post by btilly »

gshulegaard wrote: post #33
aristus wrote: post #18

Bah. People keep confusing the syntax with the data model. SQL is simply a notation to express theorems in relational set theory. It's pretty much the only pure-functional, side-effect-free programming language that's actually gone mainstream [0]. If you look carefully at the APIs of the "No SQL" databases, you'll find them introducing relational set theoretic features. To paraphrase Paul Graham's unbearably smug com…

This is interesting, but I admit I am a bit confused. Having read "An Introduction to Database Systems" by C.J. Date ( http://www.amazon.com/Introduction-Database-Systems-8th/dp/0... ), I have a tremendous appreciation for Relational Algebra and Theory which allows for the closed functional nature/syntax of SQL which holds true across the various normal forms (1st-5th). Perhaps due to my own lack of understanding, I…

Syntax and being relational are orthogonal.

You can set up non-relational data structures in SQL. You can set up a relational data structure in virtually any programming language.

However what the NoSQL people are learning is that smart developers really want relational models. So they are offering the features that can be used to achieve that.

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