attilahorvath

# compress
tar -czvf archive.tar.gz directory

# extract
tar -xzvf archive.tar.gz

# flags:
# (c)reate
# e(x)tract
# use g(z)ip

attilahorvath

class MigrateToUtf8mb4 < ActiveRecord::Migration
  def change
    execute "ALTER DATABASE `#{ActiveRecord::Base.connection.current_database}` CHARACTER SET utf8mb4;"

    ActiveRecord::Base.connection.tables.each do |table|
      execute "ALTER TABLE `#{table}` CHARACTER SET = utf8mb4 COLLATE utf8mb4_unicode_ci;"
      ActiveRecord::Base.connection.columns(table).each do |column|
        if column.sql_type =~ /varchar\((\d+)\)/
          limit = $1.to_i
          limit = 191 if ActiveRecord::Base.connection.indexes(table).any?{|i| i.columns.include? column.name} && limit > 191