gitlab-org--gitlab-foss/app/finders
Toon Claes a488fc0add Add workaround for UPDATE with subquery when using MySQL
When trying to run an UPDATE, this query is ran:

```sql
UPDATE `todos`
INNER JOIN `projects` ON `projects`.`id` = `todos`.`project_id`
SET `todos`.`state` = 'done'
WHERE `todos`.`user_id` = 4
  AND (`todos`.`state` IN ('pending'))
  AND (EXISTS
         (SELECT 1
          FROM `project_authorizations`
          WHERE `project_authorizations`.`user_id` = 4
            AND (project_authorizations.project_id = projects.id))
       OR projects.visibility_level IN (10,
                                        20))
  AND `projects`.`id` IN
    (SELECT `todos`.`project_id`
     FROM `todos`
     WHERE `todos`.`user_id` = 4
       AND (`todos`.`state` IN ('pending')))
  AND (`todos`.`state` != 'done')
```

But MySQL does not like the subquery used to filter on
`projects.id IN (SELECT ...`

Because the subquery queries from the same table:

> Error: You can’t specify target table ‘todos’ for update in FROM clause

So as workaround, wrap it in another subquery, where the original
subquery is aliased using the `AS` statement.

Mostly inspired by https://stackoverflow.com/a/43610081/89376
2017-08-03 16:31:05 +02:00
..
admin Decrease ABC threshold to 56.96 2017-07-24 10:54:16 +00:00
concerns move CreatedAtFilter to concerns folder 2017-07-07 19:01:49 +02:00
access_requests_finder.rb
branches_finder.rb
contributed_projects_finder.rb
environments_finder.rb Revert "Enable Style/DotPosition" 2017-02-23 09:33:19 -06:00
events_finder.rb Enable Style/DotPosition Rubocop 👮 2017-06-21 13:48:12 +00:00
group_finder.rb Merge branch 'jej-group-name-disclosure' into 'security' 2017-03-29 19:18:38 -07:00
group_members_finder.rb Enable Style/DotPosition Rubocop 👮 2017-06-21 13:48:12 +00:00
group_projects_finder.rb Refactor GroupProjectsFinder#init_collection 2017-06-19 19:11:35 +02:00
groups_finder.rb Make the GroupFinder specs more strict 2017-06-15 08:46:34 +02:00
issuable_finder.rb Merge issuable "reopened" state into "opened" 2017-07-28 13:31:51 +02:00
issues_finder.rb Clear issuable counter caches on update 2017-07-19 10:21:20 +01:00
joined_groups_finder.rb
labels_finder.rb Hide archived project labels from group issue tracker 2017-06-30 16:22:00 -03:00
members_finder.rb Show members of parent groups on project members page 2017-03-09 10:23:57 +02:00
merge_requests_finder.rb Add top-level /merge_requests API endpoint 2017-07-27 23:34:57 +02:00
milestones_finder.rb fix milestones finder failing spec 2017-07-07 19:21:00 -03:00
move_to_project_finder.rb
notes_finder.rb Merge branch 'snippets-finder-visibility' into 'security' 2017-05-10 16:48:18 +02:00
personal_access_tokens_finder.rb apply codestyle and implementation changes to the respective feature code 2017-03-06 19:18:26 +00:00
personal_projects_finder.rb
pipeline_schedules_finder.rb Add Pipeline Schedules that supersedes experimental Trigger Schedule 2017-05-07 22:35:56 +00:00
pipelines_finder.rb Add constant as ALLOWED_INDEXED_COLUMNS 2017-05-03 02:11:51 +09:00
projects_finder.rb Add user projects API 2017-07-06 08:04:54 +03:00
README.md
snippets_finder.rb Merge branch 'snippets-finder-visibility' into 'security' 2017-05-10 16:48:18 +02:00
tags_finder.rb
todos_finder.rb Add workaround for UPDATE with subquery when using MySQL 2017-08-03 16:31:05 +02:00
union_finder.rb
users_finder.rb refactor created at filter to use model scopes 2017-07-07 18:31:50 +02:00

Finders

This type of classes responsible for collection items based on different conditions. To prevent lookup methods in models like this:

class Project
  def issues_for_user_filtered_by(user, filter)
    # A lot of logic not related to project model itself
  end
end

issues = project.issues_for_user_filtered_by(user, params)

Better use this:

issues = IssuesFinder.new(project, user, filter).execute

It will help keep models thiner.