diff options
Diffstat (limited to 'guides/source/active_record_querying.md')
| -rw-r--r-- | guides/source/active_record_querying.md | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md index 2f10bc4e7c..c0a4a0ba39 100644 --- a/guides/source/active_record_querying.md +++ b/guides/source/active_record_querying.md @@ -341,8 +341,6 @@ User.find_each(begin_at: 2000, batch_size: 5000) do |user| end ``` -Another example would be if you wanted multiple workers handling the same processing queue. You could have each worker handle 10000 records by setting the appropriate `:begin_at` option on each worker. - **`:end_at`** Similar to the `:begin_at` option, `:end_at` allows you to configure the last ID of the sequence whenever the highest ID is not the one you need. @@ -356,6 +354,10 @@ User.find_each(begin_at: 2000, end_at: 10000, batch_size: 5000) do |user| end ``` +Another example would be if you wanted multiple workers handling the same +processing queue. You could have each worker handle 10000 records by setting the +appropriate `:begin_at` and `:end_at` options on each worker. + #### `find_in_batches` The `find_in_batches` method is similar to `find_each`, since both retrieve batches of records. The difference is that `find_in_batches` yields _batches_ to the block as an array of models, instead of individually. The following example will yield to the supplied block an array of up to 1000 invoices at a time, with the final block containing any remaining invoices: @@ -898,7 +900,7 @@ For example: Item.transaction do i = Item.lock.first i.name = 'Jones' - i.save + i.save! end ``` @@ -1266,6 +1268,18 @@ class Client < ActiveRecord::Base end ``` +NOTE: The `default_scope` is also applied while creating/building a record. +It is not applied while updating a record. E.g.: + +```ruby +class Client < ActiveRecord::Base + default_scope { where(active: true) } +end + +Client.new # => #<Client id: nil, active: true> +Client.unscoped.new # => #<Client id: nil, active: nil> +``` + ### Merging of scopes Just like `where` clauses scopes are merged using `AND` conditions. @@ -1787,8 +1801,9 @@ EXPLAIN for: SELECT `users`.* FROM `users` INNER JOIN `articles` ON `articles`.` under MySQL. -Active Record performs a pretty printing that emulates the one of the database -shells. So, the same query running with the PostgreSQL adapter would yield instead +Active Record performs a pretty printing that emulates that of the +corresponding database shell. So, the same query running with the +PostgreSQL adapter would yield instead ``` EXPLAIN for: SELECT "users".* FROM "users" INNER JOIN "articles" ON "articles"."user_id" = "users"."id" WHERE "users"."id" = 1 |