Support for SQL Server on Rails 5.x, 6.x, and 7.x

[JesseChavez]

Hi All,

I have done some work to support the SQL Server / Azure SQL, it is mostly based on the sqlserver arel
visitor from the CRuby activerecord-sqlserver-adapter gem.

At the moment passes most of its tests and activerecord tests with few exceptions, the failing test are due
SQL server specific ways to do things such as:

• Average respects the data type columns so the avg of a integer column the result is integer
• A column has been specified more than once in the order by list throws an error, this kind of scenario
  gets ignored by Postgres.
• transaction isolation level repeatable_read and read_committed protect the read with a lock.
• SQL Server can't update identity keys
• etc.

NOTES:
To avoid the locking in read_committed we need to do:

"ALTER DATABASE [db_name] SET READ_COMMITTED_SNAPSHOT ON WITH ROLLBACK IMMEDIATE"

The activerecord tests run against my rails fork which contains specific fixes to run the test such as decimal max precision 38, quoting for SQL Server, etc. Please look at my commit in the rails fork.

https://github.com/JesseChavez/rails/tree/5-0-stable-dev

[JesseChavez]

Just for reference if there is anyone still interested on an Active Record SQL Server adapter the works with JRuby

There is a fork of the activerecord-jdbc-adapter with Rails 5.0, 5.1, 5.2, 6.0. and 6.1 support:

https://rubygems.org/gems/activerecord-jdbc-alt-adapter

It is strongly advised to read the README file of the forked repository for more information and differences compared to activerecord-sqlserver-adapter or activerecord-jdbc-adapter adapters.

platforms :jruby do
  gem 'activerecord-jdbc-alt-adapter', '~> 61.0.0'
  gem 'jdbc-mssql', '~> 0.9.0'
end

Some of our apps are already running in production and one of them is a huge ancient finance Rails app originally created with Rails 2.0 and JRuby.

[JesseChavez]

Support for Rails 7.1 and 7.2 might have bugs

[headius]

I remember SQL Server coming up in a recent discussion, but I can't remember who. Perhaps @rsim has customers using SQL Server? I know @rdubya used to use it but things have changed there?

[enebo]

From what I remember @rdubya forked and updated our own codebase to make: https://github.com/jruby/activerecord-jdbcsqlserver-adapter . This was very similar in spirit to how the other adapters are in mainline arjdbc and I think @JesseChavez has his own version. I honestly do not remember the differences between the two but I know there was a discussion about the approaches at one point.

[enebo]

@JesseChavez I am happy to merge this so long as you are happy to keep updating it or at least advising on reported issues.