Class: Rotulus::Column

Inherits:
Object
  • Object
show all
Defined in:
lib/rotulus/column.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model, name, direction: :asc, nullable: nil, nulls: nil, distinct: nil) ⇒ Column

Creates a Column object representing a table column in the “ORDER BY” expression.



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# File 'lib/rotulus/column.rb', line 26

def initialize(model, name, direction: :asc, nullable: nil, nulls: nil, distinct: nil)
  @model = model
  @name = name.to_s
  validate_name!

  @direction = sort_direction(direction)
  @distinct = uniqueness(distinct)
  @nullable = nullability(nullable)
  @nulls = nulls_order(nulls)
end

Instance Attribute Details

#direction ⇒ Object (readonly)

Returns the value of attribute direction.



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# File 'lib/rotulus/column.rb', line 3

def direction
  @direction
end

#model ⇒ Object (readonly)

Returns the value of attribute model.



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# File 'lib/rotulus/column.rb', line 3

def model
  @model
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/rotulus/column.rb', line 3

def name
  @name
end

#nulls ⇒ Object (readonly)

Returns the value of attribute nulls.



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# File 'lib/rotulus/column.rb', line 3

def nulls
  @nulls
end

Class Method Details

.select_alias(name) ⇒ Object 



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# File 'lib/rotulus/column.rb', line 41

def self.select_alias(name)
  "cursor___#{name.to_s.gsub('.', '__')}"
end

.select_alias_to_name(select_alias) ⇒ Object 



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# File 'lib/rotulus/column.rb', line 37

def self.select_alias_to_name(select_alias)
  select_alias.gsub('cursor___', '').gsub('__', '.')
end

Instance Method Details

#as_leftmost! ⇒ Object

Mark the column as the ‘leftmost’ column in the ‘ORDER BY’ SQL (column with highest sort priority)



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# File 'lib/rotulus/column.rb', line 46

def as_leftmost!
  @leftmost = true

  self
end

#asc? ⇒ Boolean 



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# File 'lib/rotulus/column.rb', line 56

def asc?
  direction == :asc
end

#desc? ⇒ Boolean 



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# File 'lib/rotulus/column.rb', line 60

def desc?
  !asc?
end

#distinct? ⇒ Boolean 



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# File 'lib/rotulus/column.rb', line 64

def distinct?
  @distinct
end

#leftmost? ⇒ Boolean 



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# File 'lib/rotulus/column.rb', line 52

def leftmost?
  @leftmost
end

#nullable? ⇒ Boolean 



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# File 'lib/rotulus/column.rb', line 68

def nullable?
  @nullable
end

#nulls_first? ⇒ Boolean 



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# File 'lib/rotulus/column.rb', line 72

def nulls_first?
  nulls == :first
end

#nulls_last? ⇒ Boolean 



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# File 'lib/rotulus/column.rb', line 76

def nulls_last?
  nulls == :last
end

#order_sql ⇒ Object 



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# File 'lib/rotulus/column.rb', line 113

def order_sql
  return Rotulus.db.order_sql(prefixed_name, direction) unless nullable?

  Rotulus.db.nullable_order_sql(prefixed_name, direction, nulls)
end

#prefixed_name ⇒ Object 



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# File 'lib/rotulus/column.rb', line 84

def prefixed_name
  @prefixed_name ||= if !name_has_prefix?
                       "#{model.table_name}.#{name}"
                     else
                       name
                     end
end

#reversed_order_sql ⇒ Object 



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# File 'lib/rotulus/column.rb', line 107

def reversed_order_sql
  return Rotulus.db.reversed_order_sql(prefixed_name, direction) unless nullable?

  Rotulus.db.reversed_nullable_order_sql(prefixed_name, direction, nulls)
end

#select_alias ⇒ Object 



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# File 'lib/rotulus/column.rb', line 92

def select_alias
  self.class.select_alias(prefixed_name)
end

#select_sql ⇒ Object 



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# File 'lib/rotulus/column.rb', line 119

def select_sql
  "#{prefixed_name} as #{select_alias}"
end

#to_h ⇒ Object 



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# File 'lib/rotulus/column.rb', line 96

def to_h
  h = {
    direction: direction,
    nullable: nullable?,
    distinct: distinct?
  }
  h[:nulls] = nulls if nullable?

  { prefixed_name => h }
end

#unprefixed_name ⇒ Object 



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# File 'lib/rotulus/column.rb', line 80

def unprefixed_name
  @unprefixed_name ||= name.split('.').last
end