Class: Graffiti::SquishSelect

Inherits:
SquishQuery show all
Defined in:
lib/graffiti/squish.rb

Constant Summary

Constants inherited from SquishQuery

Graffiti::SquishQuery::AGGREGATE, Graffiti::SquishQuery::BN, Graffiti::SquishQuery::BN_SCAN, Graffiti::SquishQuery::INTERNAL, Graffiti::SquishQuery::LITERAL, Graffiti::SquishQuery::LITERAL_SCAN, Graffiti::SquishQuery::NUMBER, Graffiti::SquishQuery::OPERATOR, Graffiti::SquishQuery::PARAMETER, Graffiti::SquishQuery::PARAMETER_AND_LITERAL_SCAN, Graffiti::SquishQuery::QUERY

Instance Attribute Summary

Attributes inherited from SquishQuery

#group, #literal, #nodes, #ns, #order, #order_dir, #pattern, #variables

Instance Method Summary collapse

Methods inherited from SquishQuery

#ns_shrink, ns_shrink, #substitute_literals, #to_s, uri_shrink!, #validate_expression

Constructor Details

#initialize(config, query) ⇒ SquishSelect

Returns a new instance of SquishSelect.



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# File 'lib/graffiti/squish.rb', line 267

def initialize(config, query)
  super(config, query)

  if @key   # initialized from a String, not a Hash
    'SELECT' == @key or raise ProgrammingError,
      'Wrong query type: SELECT expected intead of ' + @key

    @nodes = @nodes.split(/\s*,\s*/).map {|node|
      validate_expression(node)
    }
  end
end

Instance Method Details

#to_sql ⇒ Object

translate Squish SELECT query to SQL



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# File 'lib/graffiti/squish.rb', line 282

def to_sql
  where = @sql_mapper.where

  select = @nodes.dup
  select.push(@order) unless @order.empty? or @nodes.include?(@order)

  # now put it all together
  sql = %{\nFROM #{@sql_mapper.from}}
  sql << %{\nWHERE #{where}} unless where.empty?
  sql << %{\nGROUP BY #{@group}} unless @group.empty?
  sql << %{\nORDER BY #{@order} #{@order_dir}} unless @order.empty?

  select = select.map do |expr|
    bind_blank_nodes(expr) + (BN.match(expr) ? (' AS ' + $1) : '')
  end
  sql = 'SELECT DISTINCT ' << select.join(', ') << bind_blank_nodes(sql)

  sql =~ /\?/ and raise ProgrammingError,
    "Unexpected '?' in translated query (probably, caused by unmapped blank node): #{sql.gsub(/\s+/, ' ')};"

  substitute_literals(sql)
end