What do you mean SQL is bad? SQL is very good and some dialects can do some amazing things. I don't think EF is much better, and EF (older Linq2Sql as well) has some gotchas because it converts your expression into SQL, except for when it doesn't and throws a runtime error that it couldn't. And there are some edge cases where you think a C# expression would convert to SQL but alas, it wont.
The foundation theory is the relational model of data, and the use of operators from relational algebra. So, we use relations to represent the data in the application domain, and use the operators of relational algebra to take relational inputs and produce relational outputs. It's an extensible and composable model.
When we solve problems using relations, we benefit by thinking in terms of relations.
We can ask: How well does SQL allow us to express an algorithm in relational terms? (Let's ignore that that SQL introduces some non-relational impurities that may have practical value - eg column order, row order, duplicate rows.)
When I examine an SQL expression, and then visualize the relational operators involved, I find a very poor correspondence between the SQL expression and the relational algebra. I need to basically read the entire statement to understand the parts. (Contast to the LINQ examples, or perhaps a shell pipline.) In a way, this is the substance of the original article.
Thanks. Even on just that point, I disagree. I think they are equally readable. Just like Python and C# are equally readable to the respective cohorts that are used to programming in those languages.
Yes, EF queries are more readable to many developers who know C# well but don't want to get used to SQL. But the problem with that is DB apathy + EF leads to some real performance problems as systems scale that grinds the application to a halt with SQL queries longer than dissertations, to which the developers need a quick hack to fix. The query plan for those beasts is intractable. Which of the 10 table scans or index scans to tackle first? And how do you tackle it?
They discover "indexed views" and all is well until you start to have locking problems, so more hacks are needed. etc. By writing the damn SQL to begin with they'd have to tame the beast earlier on and address the design flaws in their schema and/or application.
Ok this is a bit of a strawman (although it is based on experience) but I think saying SQL is less readable is a red herring. It is more readable for a lot of use cases. It's a DSL designed for the job, you really can't get much better (except for Elastic Search use cases, etc.). It's slightly old fashioned but that's just fashion.
This isn't about ORMs or database performance. It's just a comparison of query languages, with LINQ being more natural for data models with lots of joins and nested records that are common today (especially since that's how people work with objects inside their programming language).
SQL is far from perfect. It would be nice to see some modern SQL dialects that follow the LINQ syntax and are natively supported by RDBMS.
> "Yes, EF queries are more readable to many developers who know C# well but don't want to get used to SQL."
My main field is databases. Been working with SQL for ~15 years. My knowledge of LINQ is much less than SQL (partly also because I was writing plenty of SQL before LINQ existed).
I also think SQL is a big big mess full of leaky abstractions that forces you to do things in unituitive ways. And yet it is incredibly powerful. But don't listen to me. Read any book by C.J.Date (especially this one http://www.thethirdmanifesto.com/), for all the reasons SQL is poorly designed.
> "But the problem with that is DB apathy.....leads to some real performance problems....."
I completely agree. Databases are very powerful and more people should know how to properly use them so that the rest of us would have fewer headaches.
> " It's a DSL designed for the job, you really can't get much better"
The problem is that due to many reasons it is the only such DSL in wide spread use. Any alternatives are just footnotes.
