Class: ROM::SQL::Header

Inherits:
Object
  • Object
show all
Defined in:
lib/rom/sql/header.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(columns, table) ⇒ Header

Returns a new instance of Header.



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# File 'lib/rom/sql/header.rb', line 9

def initialize(columns, table)
  @columns = columns
  @table = table
end

Instance Attribute Details

#columns ⇒ Object (readonly)

Returns the value of attribute columns.



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# File 'lib/rom/sql/header.rb', line 7

def columns
  @columns
end

#table ⇒ Object (readonly)

Returns the value of attribute table.



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# File 'lib/rom/sql/header.rb', line 7

def table
  @table
end

Instance Method Details

#names ⇒ Object 



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# File 'lib/rom/sql/header.rb', line 26

def names
  columns.map { |col| :"#{col.to_s.split('___').last}" }
end

#prefix(col_prefix) ⇒ Object 



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# File 'lib/rom/sql/header.rb', line 50

def prefix(col_prefix)
  rename(Hash[columns.map { |col| [col, :"#{col_prefix}_#{col}"] }])
end

#project(*names) ⇒ Object 



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# File 'lib/rom/sql/header.rb', line 30

def project(*names)
  self.class.new(columns.find_all { |col| names.include?(col) }, table)
end

#qualified ⇒ Object 



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# File 'lib/rom/sql/header.rb', line 34

def qualified
  self.class.new(columns.map { |col| :"#{table}__#{col}" }, table)
end

#rename(options) ⇒ Object 



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# File 'lib/rom/sql/header.rb', line 38

def rename(options)
  self.class.new(columns.map { |col|
    new_name = options[col]

    if new_name
      :"#{col}___#{new_name}"
    else
      col
    end
  }, table)
end

#to_ary ⇒ Object Also known as: to_a 



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# File 'lib/rom/sql/header.rb', line 14

def to_ary
  columns
end

#to_h ⇒ Object 



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# File 'lib/rom/sql/header.rb', line 19

def to_h
  columns.each_with_object({}) do |col, h|
    left, right = col.to_s.split('___')
    h[left.to_sym] = (right || left).to_sym
  end
end