Scopes

Scope provides elegant way to write commonly used query fragments and improve readability of your code. Scope returns a new collection Collection or taint the current Collection.
Let's get an example:
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class User
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    include Clear::Model
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​
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    primary_key
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​
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    column role : String
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    column role_level : Int32
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    column email : String
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    column active : Bool
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​
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    scope :with_privileges do |level|
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        where{ role.in?(%w(superadmin admin)) | (role_level > level) }
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    end
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    scope(:active){ where(active: true) }
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end
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​
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# Later one:
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User.with_privileges(3).each do |x|
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    puts "Admin #{x.id} - #{x.email}"
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end
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Scope can be easily chained and you can pass argument to them too:
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User.with_admin_privileges(4).active
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Scope live both in Model::Collection and Model code space, meaning you may ignore Model.query to start a new Collection but instead go straight to Model.scope.

Window and CTE

Next - Querying

Writing low-level SQL

Last modified 2yr ago

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