Browse files

Adding in a db dumping and loading helper

  • Loading branch information...
1 parent fba131c commit 051a1f56ff26bc79d204452900b5f66d8d213739 @konklone konklone committed Sep 4, 2009
Showing with 203 additions and 0 deletions.
  1. +23 −0 lib/tasks/yaml_db_tasks.rake
  2. +180 −0 lib/yaml_db.rb
View
23 lib/tasks/yaml_db_tasks.rake
@@ -0,0 +1,23 @@
+namespace :db do
+ desc "Dump schema and data to db/schema.rb and db/data.yml"
+ task(:dump => [ "db:schema:dump", "db:data:dump" ])
+
+ desc "Load schema and data from db/schema.rb and db/data.yml"
+ task(:load => [ "db:schema:load", "db:data:load" ])
+
+ namespace :data do
+ def db_dump_data_file
+ "#{RAILS_ROOT}/db/data.yml"
+ end
+
+ desc "Dump contents of database to db/data.yml"
+ task(:dump => :environment) do
+ YamlDb.dump db_dump_data_file
+ end
+
+ desc "Load contents of db/data.yml into database"
+ task(:load => :environment) do
+ YamlDb.load db_dump_data_file
+ end
+ end
+end
View
180 lib/yaml_db.rb
@@ -0,0 +1,180 @@
+require 'rubygems'
+require 'yaml'
+require 'active_record'
+
+
+module YamlDb
+ def self.dump(filename)
+ disable_logger
+ YamlDb::Dump.dump(File.new(filename, "w"))
+ reenable_logger
+ end
+
+ def self.load(filename)
+ disable_logger
+ YamlDb::Load.load(File.new(filename, "r"))
+ reenable_logger
+ end
+
+ def self.disable_logger
+ @@old_logger = ActiveRecord::Base.logger
+ ActiveRecord::Base.logger = nil
+ end
+
+ def self.reenable_logger
+ ActiveRecord::Base.logger = @@old_logger
+ end
+end
+
+
+module YamlDb::Utils
+ def self.chunk_records(records)
+ yaml = [ records ].to_yaml
+ yaml.sub!("--- \n", "")
+ yaml.sub!('- - -', ' - -')
+ yaml
+ end
+
+ def self.unhash(hash, keys)
+ keys.map { |key| hash[key] }
+ end
+
+ def self.unhash_records(records, keys)
+ records.each_with_index do |record, index|
+ records[index] = unhash(record, keys)
+ end
+
+ records
+ end
+
+ def self.convert_booleans(records, columns)
+ records.each do |record|
+ columns.each do |column|
+ next if is_boolean(record[column])
+ record[column] = (record[column] == 't' or record[column] == '1')
+ end
+ end
+ records
+ end
+
+ def self.boolean_columns(table)
+ columns = ActiveRecord::Base.connection.columns(table).reject { |c| c.type != :boolean }
+ columns.map { |c| c.name }
+ end
+
+ def self.is_boolean(value)
+ value.kind_of?(TrueClass) or value.kind_of?(FalseClass)
+ end
+
+ def self.quote_table(table)
+ ActiveRecord::Base.connection.quote_table_name(table)
+ end
+end
+
+
+module YamlDb::Dump
+ def self.dump(io)
+ tables.each do |table|
+ dump_table(io, table)
+ end
+ end
+
+ def self.tables
+ ActiveRecord::Base.connection.tables.reject { |table| ['schema_info', 'schema_migrations'].include?(table) }
+ end
+
+ def self.dump_table(io, table)
+ return if table_record_count(table).zero?
+
+ dump_table_columns(io, table)
+ dump_table_records(io, table)
+ end
+
+ def self.dump_table_columns(io, table)
+ io.write("\n")
+ io.write({ table => { 'columns' => table_column_names(table) } }.to_yaml)
+ end
+
+ def self.dump_table_records(io, table)
+ table_record_header(io)
+
+ column_names = table_column_names(table)
+
+ each_table_page(table) do |records|
+ rows = YamlDb::Utils.unhash_records(records, column_names)
+ io.write(YamlDb::Utils.chunk_records(records))
+ end
+ end
+
+ def self.table_record_header(io)
+ io.write(" records: \n")
+ end
+
+ def self.table_column_names(table)
+ ActiveRecord::Base.connection.columns(table).map { |c| c.name }
+ end
+
+ def self.each_table_page(table, records_per_page=1000)
+ total_count = table_record_count(table)
+ pages = (total_count.to_f / records_per_page).ceil - 1
+ id = table_column_names(table).first
+ boolean_columns = YamlDb::Utils.boolean_columns(table)
+ quoted_table_name = YamlDb::Utils.quote_table(table)
+
+ (0..pages).to_a.each do |page|
+ sql = ActiveRecord::Base.connection.add_limit_offset!("SELECT * FROM #{quoted_table_name} ORDER BY #{id}",
+ :limit => records_per_page, :offset => records_per_page * page
+ )
+ records = ActiveRecord::Base.connection.select_all(sql)
+ records = YamlDb::Utils.convert_booleans(records, boolean_columns)
+ yield records
+ end
+ end
+
+ def self.table_record_count(table)
+ ActiveRecord::Base.connection.select_one("SELECT COUNT(*) FROM #{YamlDb::Utils.quote_table(table)}").values.first.to_i
+ end
+end
+
+
+module YamlDb::Load
+ def self.load(io)
+ ActiveRecord::Base.connection.transaction do
+ YAML.load_documents(io) do |ydoc|
+ ydoc.keys.each do |table_name|
+ next if ydoc[table_name].nil?
+ load_table(table_name, ydoc[table_name])
+ end
+ end
+ end
+ end
+
+ def self.truncate_table(table)
+ begin
+ ActiveRecord::Base.connection.execute("TRUNCATE #{YamlDb::Utils.quote_table(table)}")
+ rescue Exception
+ ActiveRecord::Base.connection.execute("DELETE FROM #{YamlDb::Utils.quote_table(table)}")
+ end
+ end
+
+ def self.load_table(table, data)
+ column_names = data['columns']
+ truncate_table(table)
+ load_records(table, column_names, data['records'])
+ reset_pk_sequence!(table)
+ end
+
+ def self.load_records(table, column_names, records)
+ quoted_column_names = column_names.map { |column| ActiveRecord::Base.connection.quote_column_name(column) }.join(',')
+ quoted_table_name = YamlDb::Utils.quote_table(table)
+ records.each do |record|
+ ActiveRecord::Base.connection.execute("INSERT INTO #{quoted_table_name} (#{quoted_column_names}) VALUES (#{record.map { |r| ActiveRecord::Base.connection.quote(r) }.join(',')})")
+ end
+ end
+
+ def self.reset_pk_sequence!(table_name)
+ if ActiveRecord::Base.connection.respond_to?(:reset_pk_sequence!)
+ ActiveRecord::Base.connection.reset_pk_sequence!(table_name)
+ end
+ end
+end

0 comments on commit 051a1f5

Please sign in to comment.