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0a12a5f816
Don't use this:
scope :red, where(color: 'red')
default_scope where(color: 'red')
Use this:
scope :red, -> { where(color: 'red') }
default_scope { where(color: 'red') }
The former has numerous issues. It is a common newbie gotcha to do
the following:
scope :recent, where(published_at: Time.now - 2.weeks)
Or a more subtle variant:
scope :recent, -> { where(published_at: Time.now - 2.weeks) }
scope :recent_red, recent.where(color: 'red')
Eager scopes are also very complex to implement within Active
Record, and there are still bugs. For example, the following does
not do what you expect:
scope :remove_conditions, except(:where)
where(...).remove_conditions # => still has conditions
42 lines
2.6 KiB
Ruby
42 lines
2.6 KiB
Ruby
class Project < ActiveRecord::Base
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has_and_belongs_to_many :developers, :uniq => true, :order => 'developers.name desc, developers.id desc'
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has_and_belongs_to_many :readonly_developers, :class_name => "Developer", :readonly => true
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has_and_belongs_to_many :selected_developers, :class_name => "Developer", :select => "developers.*", :uniq => true
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has_and_belongs_to_many :non_unique_developers, :order => 'developers.name desc, developers.id desc', :class_name => 'Developer'
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has_and_belongs_to_many :limited_developers, :class_name => "Developer", :limit => 1
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has_and_belongs_to_many :developers_named_david, :class_name => "Developer", :conditions => "name = 'David'", :uniq => true
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has_and_belongs_to_many :developers_named_david_with_hash_conditions, :class_name => "Developer", :conditions => { :name => 'David' }, :uniq => true
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has_and_belongs_to_many :salaried_developers, :class_name => "Developer", :conditions => "salary > 0"
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has_and_belongs_to_many :developers_with_finder_sql, :class_name => "Developer", :finder_sql => proc { "SELECT t.*, j.* FROM developers_projects j, developers t WHERE t.id = j.developer_id AND j.project_id = #{id} ORDER BY t.id" }
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has_and_belongs_to_many :developers_with_multiline_finder_sql, :class_name => "Developer", :finder_sql => proc {
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"SELECT
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t.*, j.*
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FROM
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developers_projects j,
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developers t WHERE t.id = j.developer_id AND j.project_id = #{id} ORDER BY t.id"
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}
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has_and_belongs_to_many :developers_by_sql, :class_name => "Developer", :delete_sql => proc { |record| "DELETE FROM developers_projects WHERE project_id = #{id} AND developer_id = #{record.id}" }
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has_and_belongs_to_many :developers_with_callbacks, :class_name => "Developer", :before_add => Proc.new {|o, r| o.developers_log << "before_adding#{r.id || '<new>'}"},
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:after_add => Proc.new {|o, r| o.developers_log << "after_adding#{r.id || '<new>'}"},
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:before_remove => Proc.new {|o, r| o.developers_log << "before_removing#{r.id}"},
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:after_remove => Proc.new {|o, r| o.developers_log << "after_removing#{r.id}"}
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has_and_belongs_to_many :well_payed_salary_groups, :class_name => "Developer", :group => "developers.salary", :having => "SUM(salary) > 10000", :select => "SUM(salary) as salary"
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attr_accessor :developers_log
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after_initialize :set_developers_log
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def set_developers_log
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@developers_log = []
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end
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def self.all_as_method
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all
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end
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scope :all_as_scope, -> { scoped }
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end
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class SpecialProject < Project
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def hello_world
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"hello there!"
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end
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end
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