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document Active Record's reverse_order method

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Vijay Dev
2011-06-20 02:12:21 +05:30
committed by Xavier Noria
parent 741a417c72
commit ae8d53e586
1 changed files with 27 additions and 0 deletions
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27
railties/guides/source/active_record_querying.textile
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@@ -57,6 +57,7 @@ The methods are:
* +group+
* +order+
* +reorder+
* +reverse_order+
* +limit+
* +offset+
* +joins+
@@ -550,6 +551,32 @@ In case the +reorder+ clause is not used, the SQL executed would be:
SELECT * FROM posts WHERE id = 10 ORDER BY posted_at DESC
</sql>
h4. +reverse_order+
The +reverse_order+ method reverses the ordering clause if specified.
<ruby>
Client.where("orders_count > 10").order(:name).reverse_order
</ruby>
The SQL that would be executed:
<sql>
SELECT * FROM clients WHERE orders_count > 10 ORDER BY name DESC
</sql>
If no ordering clause is specified in the query, the +reverse_order+ orders by the primary key in reverse order.
<ruby>
Client.where("orders_count > 10").reverse_order
</ruby>
The SQL that would be executed:
<sql>
SELECT * FROM clients WHERE orders_count > 10 ORDER BY clients.id DESC
</sql>
This method accepts *no* arguments.
h3. Readonly Objects
Active Record provides +readonly+ method on a relation to explicitly disallow modification or deletion of any of the returned object. Any attempt to alter or destroy a readonly record will not succeed, raising an +ActiveRecord::ReadOnlyRecord+ exception.