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What ORMs have taught me: just learn SQL (2014)

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Re: What ORMs have taught me: just learn SQL (2014)

#241

Post by moojd »

celticmusic wrote: post #219
wvenable wrote: post #9

I use a data mapping ORM and I've literally not have any of these concerns. They are all non-issues. The first item about querying is relevant but all ORMs allow you to drop into SQL to execute a complex reporting-style query. It's not really necessary if you are just querying in objects to manipulate (which is what ORMs are good for).

A data mapper is not an ORM, it's a data mapper. It's a different access pattern. But I do agree that data mappers tend to be better.

This is the 'data mapper' vs 'active record' debate and I would argue both are sub-categories of 'Object-relational mapper.' I've seen multiple people in this thread even include query builders in their definition of ORM. I'm starting to wonder if much of the disagreement in this thread is caused by everyone having their own definition of ORM.

Re: What ORMs have taught me: just learn SQL (2014)

#242

Post by 0xDEFC0DE »

geophile wrote: post #44
wvenable wrote: post #30

Earlier quoted context omitted.

You don't use ORMs for gnarly queries -- that's not what they are for! They are for making manipulating the entities easier -- reading the data out of the database in a way that makes easy to modify. You can (and should) use them for simple queries. You have a list of entities you want to query and filter, that's going to be fine. Joins are fine. But if you're doing some complex analysis, an ORM is the wrong tool. Th…

ORMs make the simple things simple, and the complicated things impossible.

If you know SQL and know the ORM, you can just do the complicated things in SQL.

If you know a problem is going to be complicated, you know to use SQL.

If you don't know if a problem is going to be complicated, you can default to SQL and decide to use the ORM later if it's a good fit once you've got more problem details.

Re: What ORMs have taught me: just learn SQL (2014)

#243

Post by look_lookatme »

RangerScience wrote: post #26
thenewnewguy wrote: post #12

Earlier quoted context omitted.

Current rails developer here, I've found that using ActiveRecord for basic queries and moving to SQL for more complex stuff to be a very good combination. I agree that ORM users should learn SQL, but SQL and an ORM are not mutually exclusive.

Yep, also current rails dev here and this is also what I do :) Learning SQL with an ORM does remind me a bit of learning memory management with a garbage collector: helps you make better choices as to how you put things together, even if you never directly use the know-how.

Good to see y'all Rails developers out there, enjoying work and getting things done.

Re: What ORMs have taught me: just learn SQL (2014)

#244

Post by pests »

daenz wrote: post #101
wvenable wrote: post #61

Earlier quoted context omitted.

ORMs let you drop into SQL whenever you need, usually in a way that is fully compatible with the model, so that's entirely false.

Running raw user SQL isn't a prerequisite of an ORM needed to make it an "ORM", it's a useful feature that most ORMs try to include because the authors recognize the many shortcomings. Also, by writing raw engine-specific SQL, you automatically invalidate one of ORMs biggest selling points which is being SQL-database agnostic. And by "drop into", this typically means writing custom stitching code that stitches the SQ…

The PHP ORM Doctrine supports a custom SQL like language called DQL that integrates your defined model/relationships as well as converting it to the correct SQL dialect for your backing store.

Queries look like:

SELECT u FROM ForumUser u WHERE (u.username = :name OR u.username = :name2) AND u.id = :id

Where ForumUser is your model.

https://www.doctrine-project.org/projects/doctrine-orm/en/2....

Re: What ORMs have taught me: just learn SQL (2014)

#245

Post by vbezhenar »

JesseAldridge wrote: post #227

This was my position for a while. ORMs introduce a layer of magic which obscures what's actually going on under the hood. I decided I would just make raw SQL queries and handle mapping data explicitly. I quickly ended up with a lot of duplicated code. So then I thought, "Well ok, I should add a bit of abstraction on top of this..." I started coding some simple functions to help map the tabular data to objects. One th…

Sometimes you just should live with duplicated code. It's OK.

Re: What ORMs have taught me: just learn SQL (2014)

#246

Post by dymk »

vbezhenar wrote: post #245
JesseAldridge wrote: post #227

This was my position for a while. ORMs introduce a layer of magic which obscures what's actually going on under the hood. I decided I would just make raw SQL queries and handle mapping data explicitly. I quickly ended up with a lot of duplicated code. So then I thought, "Well ok, I should add a bit of abstraction on top of this..." I started coding some simple functions to help map the tabular data to objects. One th…

Sometimes you just should live with duplicated code. It's OK.

But you shouldn’t live with a hand-rolled pseudo ORM that stumbled into existence when there’s developed alternatives

Re: What ORMs have taught me: just learn SQL (2014)

#247

Post by corebit »

invokestatic wrote: post #27

This topic pops up frequently here on HN and every time I’m shocked at how many people have issues with ORMs! I’ve been using Hibernate/Spring Data for several years now and never ran into any issues. If I need to write a complex query, I can easily write a @Query annotation in HQL and it neatly fits right in to the repository class. I also develop with query logging enabled so I have better understanding of the quer…

You're not doing anything with it then. JPA is a relic that slows down productivity. Give me JDBI any day and I can get things done 10x faster.

Re: What ORMs have taught me: just learn SQL (2014)

#248

Post by chipotle_coyote »

sjwright wrote: post #233
stickfigure wrote: post #208

Beginning programmer: ORMs let me write code without learning SQL! Intermediate programmer: ORMs just get in the way! SQL isn't that hard after all. Advanced programmer: I write a lot of SQL, but I use ORMs to cut out most of the boilerplate.

Even more advanced programmer: writing the ‘boilerplate’ queries out manually takes barely more time than composing them in an ORM, means less indirection, saves me a major dependency, and encourages me to think intelligently about each query no matter how boilerplate they might seem at the surface. Super-advanced programmer: allowing my database structure to be influenced by the needs of an off-the-shelf ORM will ma…

Programmer without anything in particular to prove: hey, I already know SQL, and ORMs create queries "under the hood" in ways I can reason about and control, so I'm going to use this ORM in a way that doesn't involve just throwing objects and tables together in a big pile and mooshing them all together with duct tape.

Re: What ORMs have taught me: just learn SQL (2014)

#249

Post by brettnak »

I think a lot of this is just some weird expectations. You cannot _use_ a database without knowing sql. ORMs work great, but you have to know sql to use them properly. What if you want to load a relationship with a join? What if you want only to load certain columns?

I would consider part of the profession to be knowing sql. This whole "orms are bad / long live the orm" split attitude is ridiculous. ORMs are fine. Some orms are bad, just like some code is bad, and some frameworks are poorly thought out. I have worked with developers in the past, who I _desparately_ wish were forced to use a good ORM like ActiveRecord, so that they could understand just how far you can get with a solid and good pattern. I've also worked with developers in the past who used an ORM like a 15kg sledgehammer, and had absolutely no idea what was going on.

Re: What ORMs have taught me: just learn SQL (2014)

#250

Post by TylerE »

hardwaresofton wrote: post #240

ORMs are a leaky abstraction -- there is a sweet spot (mostly basic queries/relationships) where they provide lots of value, but there is a veritable infinity of scenarios beyond where they are a hindrance. Also they tend to introduce lots of hidden complexity when they try to introduce flexibility to match the landscape. I'd argue that most of the time what you really need is a query builder with the right combinato…

That's why you use something like SQLAlchemy that gives you all the good parts, but lets you painlessly drop down to native SQL when you have to.
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