# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 64
def self.database_exists?(config)
  !!ActiveRecord::Base.mysql2_connection(config)
rescue ActiveRecord::NoDatabaseError
  false
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 58
def initialize(connection, logger, connection_options, config)
  superclass_config = config.reverse_merge(prepared_statements: false)
  super(connection, logger, connection_options, superclass_config)
  configure_connection
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 43
def new_client(config)
  Mysql2::Client.new(config)
rescue Mysql2::Error => error
  if error.error_number == ConnectionAdapters::Mysql2Adapter::ER_BAD_DB_ERROR
    raise ActiveRecord::NoDatabaseError.db_error(config[:database])
  elsif error.error_number == ConnectionAdapters::Mysql2Adapter::ER_ACCESS_DENIED_ERROR
    raise ActiveRecord::DatabaseConnectionError.username_error(config[:username])
  elsif [ConnectionAdapters::Mysql2Adapter::ER_CONN_HOST_ERROR, ConnectionAdapters::Mysql2Adapter::ER_UNKNOWN_HOST_ERROR].include?(error.error_number)
    raise ActiveRecord::DatabaseConnectionError.hostname_error(config[:host])
  else
    raise ActiveRecord::ConnectionNotEstablished, error.message
  end
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 118
def active?
  @connection.ping
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 131
def disconnect!
  super
  @connection.close
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 100
def error_number(exception)
  exception.error_number if exception.respond_to?(:error_number)
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 108
def quote_string(string)
  @connection.escape(string)
rescue Mysql2::Error => error
  raise translate_exception(error, message: error.message, sql: "<escape>", binds: [])
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 122
def reconnect!
  super
  disconnect!
  connect
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 74
def supports_comments?
  true
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 78
def supports_comments_in_create?
  true
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 70
def supports_json?
  !mariadb? && database_version >= "5.7.8"
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 86
def supports_lazy_transactions?
  true
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 82
def supports_savepoints?
  true
end