DBIx::Class::ResultSetColumn(3)

NAME
  DBIx::Class::ResultSetColumn - helpful methods for messing
  with a single column of the resultset

SYNOPSIS
  $rs = $schema->resultset('CD')->search({ artist => 'Tool' });
  $rs_column = $rs->get_column('year');
  $max_year = $rs_column->max; #returns latest year

DESCRIPTION
A convenience class used to perform operations on a specific column of a resultset.

METHODS

  new
  my $obj = DBIx::Class::ResultSetColumn->new($rs, $column);

Creates a new resultset column object from the resultset and column passed as params. Used internally by "get_column" in DBIx::Class::ResultSet.

  as_query

Arguments: none
Return Value: \[ $sql, @bind_values ]

Returns the SQL query and bind vars associated with the invocant.

This is generally used as the RHS for a subquery.

  next

Arguments: none
Return Value: $value

Returns the next value of the column in the resultset (or "undef" if there is none).

Much like "next" in DBIx::Class::ResultSet but just returning the one value.

  all

Arguments: none
Return Value: @values

Returns all values of the column in the resultset (or "undef" if there are none).

Much like "all" in DBIx::Class::ResultSet but returns values rather than result objects.

  reset

Arguments: none
Return Value: $self

Resets the underlying resultset's cursor, so you can iterate through the elements of the column again.

Much like "reset" in DBIx::Class::ResultSet.

  first

Arguments: none
Return Value: $value

Resets the underlying resultset and returns the next value of the column in the resultset (or "undef" if there is none).

Much like "first" in DBIx::Class::ResultSet but just returning the one value.

  single

Arguments: none
Return Value: $value

Much like "single" in DBIx::Class::ResultSet fetches one and only one column value using the cursor directly. If additional rows are present a warning is issued before discarding the cursor.

  min

Arguments: none
Return Value: $lowest_value

  my $first_year = $year_col->min();

Wrapper for ->func. Returns the lowest value of the column in the resultset (or "undef" if there are none).

  min_rs

Arguments: none
Return Value: $resultset

  my $rs = $year_col->min_rs();

Wrapper for ->func_rs for function MIN().

  max

Arguments: none
Return Value: $highest_value

  my $last_year = $year_col->max();

Wrapper for ->func. Returns the highest value of the column in the resultset (or "undef" if there are none).

  max_rs

Arguments: none
Return Value: $resultset

  my $rs = $year_col->max_rs();

Wrapper for ->func_rs for function MAX().

  sum

Arguments: none
Return Value: $sum_of_values

  my $total = $prices_col->sum();

Wrapper for ->func. Returns the sum of all the values in the column of the resultset. Use on varchar-like columns at your own risk.

  sum_rs

Arguments: none
Return Value: $resultset

  my $rs = $year_col->sum_rs();

Wrapper for ->func_rs for function SUM().

  func

Arguments: $function
Return Value: $function_return_value

  $rs = $schema->resultset("CD")->search({});
  $length = $rs->get_column('title')->func('LENGTH');

Runs a query using the function on the column and returns the value. Produces the following SQL:

  SELECT LENGTH( title ) FROM cd me

  func_rs

Arguments: $function
Return Value: $resultset

Creates the resultset that "func()" uses to run its query.

  throw_exception
See "throw_exception" in DBIx::Class::Schema for details.

AUTHOR AND CONTRIBUTORS
See AUTHOR and CONTRIBUTORS in DBIx::Class

LICENSE
You may distribute this code under the same terms as Perl itself.