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Fix the readonly section

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Pratik Naik
2010-08-31 00:14:49 +01:00
parent 5a310f8335
commit 6d8fc26ce8
1 changed files with 5 additions and 11 deletions
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16
railties/guides/source/active_record_querying.textile
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@@ -509,22 +509,16 @@ This will return single order objects for each day, but only for the last month.
h4. Readonly Objects
To explicitly disallow modification/destruction of the matching records returned in a Relation object, you could chain the +readonly+ method as +true+ to the find call.
Any attempt to alter or destroy the readonly records will not succeed, raising an +ActiveRecord::ReadOnlyRecord+ exception. To set this option, specify it like this:
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.
<ruby>
Client.first.readonly(true)
</ruby>
For example, calling the following code will raise an +ActiveRecord::ReadOnlyRecord+ exception:
<ruby>
client = Client.first.readonly(true)
client.locked = false
client = Client.readonly.first
client.visits += 1
client.save
</ruby>
As +client+ is explicitly set to be a readonly object, the above code will raise an +ActiveRecord::ReadOnlyRecord+ exception when trying to calling +client.save+ with an updated value of _visists_.
h4. Locking Records for Update
Locking is helpful for preventing race conditions when updating records in the database and ensuring atomic updates.