Why does NoSQL exist? (MongoDB, Cassandra) | System Design

There are lots of design choices in NoSQL databases that differ from traditional relational databases...but why? This video dives into the high-level problem that NoSQL databases were invented to solve and why relational databases have limits to their scale.

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[professionalsd]

I'm i missing something or he didn't design the model in nosql ?

[ChoocoPunch]

Can I ask what should a NoSQL database table schema look like?
Should it looks like 0:05 ?

[saiyijinprince]

I think you missed a huge aspect about when you to choose between SQL vs NoSQL. At the end of the day, its more about picking the right tool for the job, and less about the scale of the data. If you need ACID transactions, use SQL. If you're okay with eventual consistency then NoSQL might be easier. The scale of your data is just one minor aspect you need to consider when building a system. I'd argue you can scale both types of DBs just as much as each other but it'll all come down to what kind of trade offs you're willing to make. Its not uncommon to have a combination of both NoSQL and SQL DBs, they are not mutually exclusive.

[Fikusiklol]

Good stuff!
However, what is also important apart from schema, that relational database has relatively slow writes/updates because of their index structure (B-tree) and storage mechanisms.
Apache Cassandra, afaik, has LSM tree and mem tables.
MongoDB has async I/O journaling and also has LSM tree (or does it?) in addition to B-tree.

I, personally, dont like any relational DB, but "right tool for the right job" :)

[goldenlin]

do most large scale companies use nosql then in favor of ease of storing and accessing data?

[ibrahimkoz]

Postgresql offers the same power as MongoDB when it comes to json, so there's no sense to choose MongoDB even if you want to store your data in denormalized form.

[optimusdebugger]

nitpick. We lost quantity when we went from model to table on order_product table

[v.demchenko]

Is it possible to just explain it in really simple way? After 6 minutes I still doesn't understand about what are you talking about. For the what reason you give this examples for SQL scaling problems for the whole video??? Redicilous...

[sbera]

Not a clear example.. needs lot of work:(