Class: BetterSeeder::Exporters::Sql

Inherits:
Base
  • Object
show all
Defined in:
lib/better_seeder/exporters/sql.rb

Instance Attribute Summary

Attributes inherited from Base

#data, #output_path, #table_name

Instance Method Summary collapse

Methods inherited from Base

#ensure_output_directory, #full_output_path, #initialize, #output_directory

Constructor Details

This class inherits a constructor from BetterSeeder::Exporters::Base

Instance Method Details

#export ⇒ Object

Esporta i dati in formato SQL, generando una singola istruzione INSERT che inserisce in blocco tutti i record.

Il metodo costruisce una stringa con la sintassi: INSERT INTO table_name (col1, col2, …) VALUES

(val11, val12, ...),
(val21, val22, ...),
... ;



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# File 'lib/better_seeder/exporters/sql.rb', line 14

def export
  return if data.empty?

  columns = data.first.keys

  # Crea l'array delle tuple di valori per ciascun record.
  values_list = data.map do |row|
    row_values = columns.map do |col|
      value = row[col]
      # Se il valore è nil restituisce NULL, altrimenti esegue l'escaping delle virgolette singole.
      value.nil? ? 'NULL' : "'#{value.to_s.gsub("'", "''")}'"
    end
    "(#{row_values.join(', ')})"
  end

  # Costruisce la query INSERT unica
  insert_statement = "INSERT INTO #{table_name} (#{columns.join(', ')}) VALUES #{values_list.join(', ')};"

  full_path = File.join(full_output_path)

  File.open(full_path, 'w') do |file|
    file.puts(insert_statement)
  end
end

#extension ⇒ Object 



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# File 'lib/better_seeder/exporters/sql.rb', line 39

def extension
  '.sql'
end