Posted by Piotr Solnica on April 24, 2019 under

We're happy to announce the release of rom 5.0.0 and rom-sql 3.0.0 . Core libraries have been upgraded to work with dry-types 1.0.0 and as a result, schema types can now benefit from all the new dry-types features. Many significant improvements have been introduced in rom-sql , let's take a look at some of the new features.

Support for arbitrary join conditions

It is now possible to set arbitrary join conditions via new DSL:

users . join ( tasks ) { | users :, tasks :| tasks [ :user_id ]. is ( users [ :id ]) & users [ :name ]. is ( 'John' ) }

This will produce the following SQL:

SELECT "users" . "id" , "users" . "name" FROM "users" INNER JOIN "tasks" ON (( "tasks" . "user_id" = "users" . "id" ) AND ( "users" . "name" = 'John' )) ORDER BY "users" . "id"

Support for CASE statements

We've also made it simple to construct CASE statements, using the following DSL:

users . select_append { id . case ( 1 => string ( 'one' ), else: string ( 'something else' )). as ( :one_or_else ) }

This will produce the following SQL:

SELECT "users" . "id" , "users" . "name" , ( CASE "users" . "id" WHEN 1 THEN 'one' ELSE 'something else' END ) AS "one_or_else" FROM "users" ORDER BY "users" . "id"

Support for exists in Projection DSL

Support for Relation#exists was added in 2.0.0 , now it is also available within the Projection DSL. Here's an example:

users . select_append { | posts: | exists ( posts . where ( posts [ :user_id ] => id )). as ( :has_posts ) }

This will produce the following SQL:

SELECT "users" . "id" , "users" . "name" , ( EXISTS ( SELECT "tasks" . "id" , "tasks" . "user_id" , "tasks" . "title" FROM "tasks" WHERE ( "tasks" . "user_id" = "users" . "id" ) ORDER BY "tasks" . "id" )) AS "has_tasks" FROM "users" ORDER BY "users" . "id"

Improved pluck support

You can now select more than one attribute when using Relation#pluck :

users . pluck ( :id , :name ) # [[1, "Jane"], [2, "Joe"], [3, "Jane"], [4, "John"]]

Originally we had an ambitious roadmap for 5.0.0 release, but its scope was simplified so that we could ship it faster, otherwise people would be blocked with upgrading for too long. This means that everything else that didn't get into 5.0.0 will be either implemented in 5.x series, or 6.0.0 .

You can also expect new releases of rom-elasticsearch , rom-http and rom-yaml adapters soon.

Release information and upgrading

This is a major release with breaking changes. Please refer to the upgrade guide for more information. As part of 5.0.0, following gems have been released:

rom 5.0.0 CHANGELOG

CHANGELOG rom-sql 3.0.0 CHANGELOG

CHANGELOG rom-factory 0.8.0 CHANGELOG

If you're having problems with the upgrade, please ask questions on discussion forum or our community chat.