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Diffstat (limited to 'guides/source/active_record_querying.md')
| -rw-r--r-- | guides/source/active_record_querying.md | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md index 7355f6816c..c4d69908ed 100644 --- a/guides/source/active_record_querying.md +++ b/guides/source/active_record_querying.md @@ -506,19 +506,15 @@ This code will generate SQL like this: SELECT * FROM clients WHERE (clients.orders_count IN (1,3,5)) ``` -### NOT, LIKE, and NOT LIKE Conditions +### NOT Conditions -`NOT`, `LIKE`, and `NOT LIKE` SQL queries can be built by `where.not`, `where.like`, and `where.not_like` respectively. +`NOT` SQL queries can be built by `where.not`. ```ruby Post.where.not(author: author) - -Author.where.like(name: 'Nari%') - -Developer.where.not_like(name: 'Tenderl%') ``` -In other words, these sort of queries can be generated by calling `where` with no argument, then immediately chain with `not`, `like`, or `not_like` passing `where` conditions. +In other words, this query can be generated by calling `where` with no argument, then immediately chain with `not` passing `where` conditions. Ordering -------- @@ -711,7 +707,7 @@ Post.order('id DESC').limit(20).unscope(:order, :limit) = Post.all You can additionally unscope specific where clauses. For example: ```ruby -Post.where(:id => 10).limit(1).unscope(:where => :id, :limit).order('id DESC') = Post.order('id DESC') +Post.where(:id => 10).limit(1).unscope(where: :id, :limit).order('id DESC') = Post.order('id DESC') ``` ### `only` @@ -736,7 +732,7 @@ The `reorder` method overrides the default scope order. For example: class Post < ActiveRecord::Base .. .. - has_many :comments, order: 'posted_at DESC' + has_many :comments, -> { order('posted_at DESC') } end Post.find(10).comments.reorder('name') @@ -971,7 +967,7 @@ SELECT categories.* FROM categories INNER JOIN posts ON posts.category_id = categories.id ``` -Or, in English: "return a Category object for all categories with posts". Note that you will see duplicate categories if more than one post has the same category. If you want unique categories, you can use `Category.joins(:posts).select("distinct(categories.id)")`. +Or, in English: "return a Category object for all categories with posts". Note that you will see duplicate categories if more than one post has the same category. If you want unique categories, you can use `Category.joins(:posts).uniq`. #### Joining Multiple Associations @@ -1206,6 +1202,7 @@ class User < ActiveRecord::Base scope :active, -> { where state: 'active' } scope :inactive, -> { where state: 'inactive' } end +``` ```ruby User.active.inactive @@ -1298,13 +1295,18 @@ recommended that you use the block form of `unscoped`: ```ruby Client.unscoped { - Client.created_before(Time.zome.now) + Client.created_before(Time.zone.now) } ``` Dynamic Finders --------------- +NOTE: Dynamic finders have been deprecated in Rails 4.0 and will be +removed in Rails 4.1. The best practice is to use Active Record scopes +instead. You can find the deprecation gem at +https://github.com/rails/activerecord-deprecated_finders + For every field (also known as an attribute) you define in your table, Active Record provides a finder method. If you have a field called `first_name` on your `Client` model for example, you get `find_by_first_name` for free from Active Record. If you have a `locked` field on the `Client` model, you also get `find_by_locked` and methods. You can specify an exclamation point (`!`) on the end of the dynamic finders to get them to raise an `ActiveRecord::RecordNotFound` error if they do not return any records, like `Client.find_by_name!("Ryan")` |