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Diffstat (limited to 'guides/source/active_record_querying.md')
-rw-r--r-- | guides/source/active_record_querying.md | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md index b518a086be..94b8453f04 100644 --- a/guides/source/active_record_querying.md +++ b/guides/source/active_record_querying.md @@ -473,7 +473,7 @@ In the case of a belongs_to relationship, an association key can be used to spec ```ruby Post.where(author: author) -Author.joins(:posts).where(posts: {author: author}) +Author.joins(:posts).where(posts: { author: author }) ``` NOTE: The values cannot be symbols. For example, you cannot do `Client.where(status: :active)`. @@ -790,6 +790,32 @@ SELECT * FROM clients WHERE orders_count > 10 ORDER BY clients.id DESC This method accepts **no** arguments. +### `rewhere` + +The `rewhere` method overrides an existing, named where condition. For example: + +```ruby +Post.where(trashed: true).rewhere(trashed: false) +``` + +The SQL that would be executed: + +```sql +SELECT * FROM posts WHERE `trashed` = 0 +``` + +In case the `rewhere` clause is not used, + +```ruby +Post.where(trashed: true).where(trashed: false) +``` + +the SQL executed would be: + +```sql +SELECT * FROM posts WHERE `trashed` = 1 AND `trashed` = 0 +``` + Null Relation ------------- @@ -1016,7 +1042,7 @@ Or, in English: "return all posts that have a comment made by a guest." #### Joining Nested Associations (Multiple Level) ```ruby -Category.joins(posts: [{comments: :guest}, :tags]) +Category.joins(posts: [{ comments: :guest }, :tags]) ``` This produces: @@ -1042,7 +1068,7 @@ An alternative and cleaner syntax is to nest the hash conditions: ```ruby time_range = (Time.now.midnight - 1.day)..Time.now.midnight -Client.joins(:orders).where(orders: {created_at: time_range}) +Client.joins(:orders).where(orders: { created_at: time_range }) ``` This will find all clients who have orders that were created yesterday, again using a `BETWEEN` SQL expression. @@ -1103,7 +1129,7 @@ This loads all the posts and the associated category and comments for each post. #### Nested Associations Hash ```ruby -Category.includes(posts: [{comments: :guest}, :tags]).find(1) +Category.includes(posts: [{ comments: :guest }, :tags]).find(1) ``` This will find the category with id 1 and eager load all of the associated posts, the associated posts' tags and comments, and every comment's guest association. @@ -1604,7 +1630,7 @@ Client.where(first_name: 'Ryan').count You can also use various finder methods on a relation for performing complex calculations: ```ruby -Client.includes("orders").where(first_name: 'Ryan', orders: {status: 'received'}).count +Client.includes("orders").where(first_name: 'Ryan', orders: { status: 'received' }).count ``` Which will execute: |