Class: Qdsl::Column

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

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, alias_name = nil, source = nil) ⇒ Column

Returns a new instance of Column.



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# File 'lib/column.rb', line 15

def initialize(name, alias_name = nil, source = nil)
  @name = name.to_s
  @alias_name = alias_name.nil? ? nil : alias_name.to_s
  @source = source
end

Instance Attribute Details

#alias_name ⇒ Object (readonly)

Returns the value of attribute alias_name.



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

def alias_name
  @alias_name
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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

def name
  @name
end

#source ⇒ Object (readonly)

Returns the value of attribute source.



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

def source
  @source
end

Class Method Details

.[](obj) ⇒ Object 



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# File 'lib/column.rb', line 5

def self.[](obj)
  if obj.is_a?(Column)
    obj
  elsif obj.is_a?(String) || obj.is_a?(Symbol)
    Column.new(obj)
  else
    raise "Cannot convert object of class \"#{obj.class.name}\" to column"
  end
end

Instance Method Details

#equals(column) ⇒ Object 



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# File 'lib/column.rb', line 50

def equals(column)
  Equals.new(self, column)
end

#exists? ⇒ Boolean

Returns:



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# File 'lib/column.rb', line 34

def exists?
  @source.column_names.include?(@name)
end

#render_sql(context, ids) ⇒ Object 



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

def render_sql(context, ids)
  SimpleRenderResult.new(@alias_name ? "#{@source.id}.#{@name} AS #{@alias_name}" : "#{@source.id}.#{@name}", {})
end

#to_expression ⇒ Object 



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# File 'lib/column.rb', line 38

def to_expression
  true?
end

#true? ⇒ Boolean

Returns:



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# File 'lib/column.rb', line 42

def true?
  IsTrue.new(self)
end

#with_alias_name(alias_name) ⇒ Object Also known as: as 



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# File 'lib/column.rb', line 25

def with_alias_name(alias_name)
  Column.new(@name, alias_name, @source)
end

#with_name(name) ⇒ Object 



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# File 'lib/column.rb', line 21

def with_name(name)
  Column.new(name, @alias_name, @source)
end

#with_source(source) ⇒ Object 



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# File 'lib/column.rb', line 30

def with_source(source)
  Column.new(@name, @alias_name, source)
end