Class: ETL::Processor::DatabaseJoinProcessor

Inherits:
RowProcessor show all
Defined in:
lib/etl/processor/database_join_processor.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from RowProcessor

#ensure_columns_available_in_row!

Constructor Details

#initialize(control, configuration) ⇒ DatabaseJoinProcessor

Initialize the procesor.

Arguments:

  • control: The ETL::Control::Control instance

  • configuration: The configuration Hash

  • definition: The source definition

Required configuration options:

  • :target: The target connection

  • :query: The join query

  • :fields: The fields to add to the row

Raises:



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# File 'lib/etl/processor/database_join_processor.rb', line 19

def initialize(control, configuration)
  super
  @target = configuration[:target]
  @query = configuration[:query]
  @fields = configuration[:fields]
  raise ControlError, ":target must be specified" unless @target
  raise ControlError, ":query must be specified" unless @query
  raise ControlError, ":fields must be specified" unless @fields
end

Instance Attribute Details

#fields ⇒ Object (readonly)

Returns the value of attribute fields.



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# File 'lib/etl/processor/database_join_processor.rb', line 6

def fields
  @fields
end

#query ⇒ Object (readonly)

Returns the value of attribute query.



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# File 'lib/etl/processor/database_join_processor.rb', line 5

def query
  @query
end

#target ⇒ Object (readonly)

Returns the value of attribute target.



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# File 'lib/etl/processor/database_join_processor.rb', line 4

def target
  @target
end

Instance Method Details

#process(row) ⇒ Object 



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# File 'lib/etl/processor/database_join_processor.rb', line 34

def process(row)
  return nil if row.nil?

  q = @query
  begin
    q = eval('"' + @query + '"')
  rescue
  end

  ETL::Engine.logger.debug("Executing select: #{q}")
  res = connection.execute(q)

  case connection
    when ActiveRecord::ConnectionAdapters::PostgreSQLAdapter;
      res.each do |r|
        @fields.each do |field|
          row[field.to_sym] = r[field.to_s]
        end
      end
    when ActiveRecord::ConnectionAdapters::MysqlAdapter;
      res.each_hash do |r|
        @fields.each do |field|
          row[field.to_sym] = r[field.to_s]
        end
      end
      res.free
    else raise "Unsupported adapter #{connection.class} for this destination"
  end

  return row
end

#to_s ⇒ Object

Get a String identifier for the source



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# File 'lib/etl/processor/database_join_processor.rb', line 30

def to_s
  "#{host}/#{database}"
end