Manager calm after ‘really good game’ at SunderlandChelsea visit Etihad on Sunday after sacking MarescaAn outwardly sanguine Pep Guardiola suggested he was reasonably content with a hard-fought poi...
Manager calm after ‘really good game’ at SunderlandChelsea visit Etihad on Sunday after sacking MarescaAn outwardly sanguine Pep Guardiola suggested he was reasonably content with a hard-fought point at Sunderland after watching his Manchester City side lose ground on Arsenal at the top of the Premier League.The 0-0 draw at the Stadium of Light leaves City second, four points behind Mikel Arteta’s leaders, but Guardiola was not too downhearted. “I’ll take the point against this team at this stadium,” said a good-humoured Guardiola, who seemed unaffected by reports that Enzo Maresca, once his assistant at the Etihad Stadium, had discussed the possibility of relocating to Manchester later this year with figures associated with City. “It was a really good game.” Continue reading...
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The Atacama Millimeter/Submillimeter Array (ALMA), the world's most powerful radio telescope, has received 145 new low-noise amplifiers (LNAs) that will increase its range and sensitivity.
ActiveRecord joins is used to combine records from multiple tables based on associations,
generating an SQL INNER JOIN.
With update_all, we can update multiple records quickly without triggering m...
ActiveRecord joins is used to combine records from multiple tables based on associations,
generating an SQL INNER JOIN.
With update_all, we can update multiple records quickly without triggering model validations, callbacks, or modifying timestamps.
Combining these two methods is useful when we need to perform bulk updates based on data from associated tables.
For example, syncing a column value from a parent record to all its children in a single query.
Before
When we use update_all together with joins,
Rails generates a subquery that prevents referencing joined tables in the SET clause,
which results in an ActiveRecord::StatementInvalid error.
For example:
class Client < ApplicationRecord
has_many :projects
end
class Project < ApplicationRecord
belongs_to :client
end
With Postgresql
Project.joins(:client).update_all("name = clients.name")
Project Update All (14.4ms) UPDATE "projects" SET name = clients.name WHERE "projects"."id" IN (SELECT "projects"."id" FROM "projects" INNER JOIN "clients" ON "clients"."id" = "projects"."client_id")
`exec_params': PG::UndefinedTable: ERROR: missing FROM-clause entry for table "clients" (ActiveRecord::StatementInvalid)
With SQLite
Project.joins(:client).update_all("name = clients.name")
Project Update All (2.4ms) UPDATE "projects" SET name = clients.name WHERE ("projects"."id") IN (SELECT "projects"."id" FROM "projects" INNER JOIN "clients" ON "clients"."id" = "projects"."client_id")
SQLite3::SQLException: no such column: clients.name: (ActiveRecord::StatementInvalid)
After
Starting from Rails 8.1,
joins in update_all is now supported for Postgresql and SQLite.
This feature was already supported by the MySQL adapter.
With MySQL
Project.joins(:client).update_all("name = clients.name")
Project Update All (0.8ms) UPDATE `projects` INNER JOIN `clients` ON `clients`.`id` = `projects`.`client_id` SET `projects`.`name` = clients.name
=> 1
With Postgresql
Project.joins(:client).update_all("name = clients.name")
Project Update All (0.5ms) UPDATE "projects" AS "__active_record_update_alias" SET name = clients.name FROM "projects" INNER JOIN "clients" ON "clients"."id" = "projects"."client_id" WHERE "projects"."id" = "__active_record_update_alias"."id"
=> 1
With SQLite
Project.joins(:client).update_all("name = clients.name")
Project Update All (0.3ms) UPDATE "projects" AS "__active_record_update_alias" SET name = clients.name FROM "projects" INNER JOIN "clients" ON "clients"."id" = "projects"."client_id" WHERE "projects"."id" = "__active_record_update_alias"."id"
=> 1
Note
This is supported as long as the relation doesn’t use a LIMIT, ORDER or GROUP BY clause.
Project.joins(:client).limit(1).update_all("name = clients.name")
Project Update All (3.9ms) UPDATE "projects" SET name = clients.name WHERE ("projects"."id") IN (SELECT "projects"."id" FROM "projects" INNER JOIN "clients" ON "clients"."id" = "projects"."client_id" LIMIT 1)
SQLite3::SQLException: no such column: clients.name: (ActiveRecord::StatementInvalid)
References
PR#53950
Rails 8.1 Release Notes
update_all API documentation
