Module: Historiographer::HistoryMigration

Included in:
ActiveRecord::ConnectionAdapters::PostgreSQL::TableDefinition, ActiveRecord::ConnectionAdapters::TableDefinition
Defined in:
lib/historiographer/history_migration.rb

Instance Method Summary collapse

Instance Method Details

#histories(except: [], only: [], no_business_columns: false, index_names: {}) ⇒ Object

class CreateAdGroupHistories < ActiveRecord::Migration

def change
  create_table :ad_group_histories do |t|
    t.histories
  end
end

end

t.histories(except: [“name”]) # don’t include name column t.histories(only: [“name”]) # only include name column t.histories(no_business_columns: true) # only add history timestamps and history_user_id; manually add your own columns

Will automatically add user_id, history_started_at, and history_ended_at columns



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# File 'lib/historiographer/history_migration.rb', line 19

def histories(except: [], only: [], no_business_columns: false, index_names: {})
  index_names.symbolize_keys!
  original_table_name = self.name.gsub(/_histories$/) {}.pluralize
  foreign_key         = original_table_name.singularize.foreign_key

  class_definer = Class.new(ActiveRecord::Base) do
  end

  class_name = original_table_name.classify
  klass      = Object.const_set(class_name, class_definer)
  original_columns = klass.columns.reject { |c| c.name == "id" || except.include?(c.name) || (only.any? && only.exclude?(c.name)) || no_business_columns }

  integer foreign_key.to_sym, null: false

  original_columns.each do |column|
    opts = {}
    opts.merge!(column.as_json.clone)

    if RUBY_VERSION.to_i >= 3
      puts "Hello"
      send(column.type, column.name, **opts.symbolize_keys!)
    else
      send(column.type, column.name, opts.symbolize_keys!)
    end
  end

  datetime :history_started_at, null: false
  datetime :history_ended_at
  integer :history_user_id

  indices_sql = %q(
    SELECT 
      DISTINCT(
        ARRAY_TO_STRING(ARRAY(
         SELECT pg_get_indexdef(idx.indexrelid, k + 1, true)
         FROM generate_subscripts(idx.indkey, 1) as k
         ORDER BY k
       ), ',')
     ) as indkey_names
    FROM pg_class t,
    pg_class i,
    pg_index idx,
    pg_attribute a,
    pg_am am
    WHERE t.oid = idx.indrelid
    AND i.oid = idx.indexrelid
    AND a.attrelid = t.oid
    AND a.attnum = ANY(idx.indkey)
    AND t.relkind = 'r'
    AND t.relname = ?;
  )

  indices_query_array = [indices_sql, original_table_name]
  indices_sanitized_query = klass.send(:sanitize_sql_array, indices_query_array)

  indexes = klass.connection.execute(indices_sanitized_query).to_a.map(&:values).flatten.reject { |i| i == "id" }.map { |i| i.split(",") }.concat([
    foreign_key,
    :history_started_at,
    :history_ended_at,
    :history_user_id
  ])

  indexes.each do |index_definition|
    index_definition = [index_definition].flatten.map(&:to_sym)
    index_name = index_definition.count == 1 ?  index_definition.first : index_definition

    if index_names.key?(index_name)
      index index_name, name: index_names[index_name]
    else
      index index_name
    end
  end

end