DBIx::Class::ResultSetColumn(3pm) User Contributed Perl Documentation DBIx::Class::ResultSetColumn(3pm)
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 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 v5.14.2 2011-05-10 DBIx::Class::ResultSetColumn(3pm)