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DBIx::Class::ResultSetColumn(3)      User Contributed Perl Documentation     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 ]

       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 row 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 varcharlike
       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.

AUTHORS
       Luke Saunders <luke.saunders@gmail.com>

       Jess Robinson

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



perl v5.16.2                                     2012-10-18                  DBIx::Class::ResultSetColumn(3)