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Export ActiveRecord Tables to CSV
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require 'csv' | |
module Exporter | |
DEFAULT_EXPORT_TABLES = [ Invoice, InvoiceItem, Item, Merchant, Transaction, User ] | |
DESTINATION_FOLDER = "tmp/" | |
def self.included(klass) | |
klass.extend ClassLevelMethods | |
end | |
def self.export_tables_to_csv(tables = DEFAULT_EXPORT_TABLES) | |
tables.each do |klass| | |
klass.send(:include, self) | |
klass.export_table_to_csv | |
end | |
end | |
def data | |
self.class.column_names.map { |column| send(column) } | |
end | |
module ClassLevelMethods | |
def export_table_to_csv | |
CSV.open(filename_for_class, "w") do |output_file| | |
output_file << column_names | |
data.each{ |row| output_file << row } | |
end | |
end | |
def filename_for_class | |
[DESTINATION_FOLDER, to_s.pluralize.underscore, '.csv'].join | |
end | |
def data | |
all.map(&:data) | |
end | |
end | |
end | |
I chose not to change Jeff's original name on the "tables" variable. Probably better named "models".
activesupport would be required implicitly since we're assuming active record models here. We could also do find_in_batches. My changes were almost entirely stylistic. Ultimately the best approach is to mysql the database's dump utility for any of this :)
(^_-) very true. This code could also work with other ORMs tho but granted using an ORM for that task seems totally overkill.
Yup, that's why there are task-oriented gems like Taps around.
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it definitely addresses my small complaint, one more pedantic comment would be the naming of
def self.export_tables_to_csv(tables = DEFAULT_EXPORT_TABLES)
. Reading this method, I would expect that the input param to be an array of DB tables. But looking at the constant definition and at the code, the expected param is actually an array of models.And since I'm at it, I would require activesupport at the top of the file since pluralize and underscore rely on it, I wouldn't call find(:all) but use a batch approach to avoid issues with big DB.
All small details tho.