Class: ROM::SQL::ProjectionDSL

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

Overview

Projection DSL used in reading API (select, select_append etc.)

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(meth, *args, &block) ⇒ Object (private)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/rom/sql/projection_dsl.rb', line 52

def method_missing(meth, *args, &block)
  if schema.key?(meth)
    schema[meth]
  else
    type = type(meth)

    if type
      if args.empty?
        ::ROM::SQL::Function.new(type, schema: schema)
      else
        ::ROM::SQL::Attribute[type].value(args[0])
      end
    else
      super
    end
  end
end

Instance Method Details

#`(value) ⇒ Attribute

Return a string literal that will be directly used in an SQL statement or query

Examples:

users.select { `'FOO'`.as(:foo) }.first
# => { :foo => "FOO" }

Parameters:

  • value (String) —

    A string object

Returns:

  • (Attribute) —

    An SQL attribute with a string literal expression



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# File 'lib/rom/sql/projection_dsl.rb', line 23

def `(value)
  expr = ::Sequel.lit(value)
  ::ROM::SQL::Attribute.new(type(:string)).meta(sql_expr: expr)
end

#function(name, *attrs) ⇒ Rom::SQL::Function Also known as: f

Return a SQL function with value Any

Examples:

users.select { function(:count, :id).as(:total) }

Parameters:

  • name (Symbol) —

    SQL function

  • attr (Symbol)

Returns:

  • (Rom::SQL::Function) 


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# File 'lib/rom/sql/projection_dsl.rb', line 39

def function(name, *attrs)
  ::ROM::SQL::Function.new(::ROM::Types::Any, schema: schema).public_send(name, *attrs)
end