Module: LegacyMigrations::RowMatchers

Defined in:
lib/legacy_migrations/row_matchers.rb

Instance Method Summary collapse

Instance Method Details

#based_on(&blk) ⇒ Object

Use ‘based_on’ to match a destination record with a source record when running an update.

This uses the matching syntax available in Thoughtbot’s Squirrel plugin where the left operator is the destination field name, and the right-hand operator is usually the source row and method.

Example

based_on do |from|
  name == from.name
  age > 17
end

The above says that if we have a destination row whose name attribute matches a source (from) row’s name, and the destination row has an age > 17, then assume the source row and destination row are the same record, and update the destination row with the source row’s data

See the thoughtbot documentation for more details about the squirrel syntax at: github.com/thoughtbot/squirrel/



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# File 'lib/legacy_migrations/row_matchers.rb', line 28

def based_on(&blk)
  @blck = blk
  @conditions = Proc.new {|from| 
    @from = from
    query = LegacyMigrations::Squirrel::Query.new(@to_table, from, &@blck)
    query.execute(:all)
  }
end