Class: Kiba::Extend::Utils::Lookup::RowSelectorByLambda

Inherits:
Object
  • Object
show all
Defined in:
lib/kiba/extend/utils/lookup/row_selector_by_lambda.rb

Overview

Called by transforms that have a conditions parameter, when a Lambda is passed in as the conditional logic. This is a more straightforward and flexible method of controlling which rows are selected/operated on than the hideous Hash conditions format.

The lambda Proc passed in must be defined with two arguments. The first should be a single data row, typically the source/target row for a data merge or other operation. The second is an array of data rows.

Because of how this RowSelector is called by different transforms, both arguments need to be defined, even if you aren’t going to use them in the logic encapsulated in the Lambda.

The lambda Proc must return an array of rows meeting the given criteria.

Examples

In your job transforms:

conditions = ->(origrow, mergerows) do
  latest = mergerows.sort_by{ |row| row[:addressid].to_i }
             .last
  [latest]
end
transform Merge::MultiRowLookup,
  lookup: addresses,
  keycolumn: :contactid,
  fieldmap: { address: :display_address, addresstype: address_category },
  conditions: conditions

Assuming addressid increments as new addresses are added, sorting the matching lookup rows by that field value, and taking the last (largest) value should ensure we are merging in only the lastest address value per contact.

In your job transforms:

conditions = ->(target, lkuprows) do
  return [] unless target[:active] == '1'

  lkuprows.select{ |row| row[:active] == '1' }
end
transform Merge::MultiRowLookup,
  lookup: addresses,
  keycolumn: :contactid,
  fieldmap: { address: :display_address, addresstype: address_category },
  conditions: conditions

This assumes the source table (listing contacts) indicates whether a contact is active or not. In addition, the addresses table indicates whether each address is active. This will cause no addresses to be merged in for inactive contacts. For active contacts, only active addresses will be merged in.

Since:

  • 2.8.0

Instance Method Summary collapse

Constructor Details

#initialize(conditions:, sep: nil) ⇒ RowSelectorByLambda

Returns a new instance of RowSelectorByLambda.

Parameters:

  • conditions (Lambda) —

    selection logic

Since:

  • 2.8.0



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# File 'lib/kiba/extend/utils/lookup/row_selector_by_lambda.rb', line 66

def initialize(conditions:, sep: nil)
  @conditions = conditions
end

Instance Method Details

#call(origrow:, mergerows:) ⇒ Object

Since:

  • 2.8.0



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# File 'lib/kiba/extend/utils/lookup/row_selector_by_lambda.rb', line 70

def call(origrow:, mergerows:)
  conditions.call(origrow, mergerows)
end