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Alzabo::Runtime::JoinCursor(3pm) User Contributed Perl Documentation Alzabo::Runtime::JoinCursor(3pm)

NAME

Alzabo::Runtime::JoinCursor - Cursor that returns arrays of "Alzabo::Runtime::Row" objects

SYNOPSIS

  use Alzabo::Runtime::JoinCursor;
  my $cursor = $schema->join( tables => [ $foo, $bar ],
                              where => [ $foo->column('foo_id'), '=', 1 ] );
  while ( my @rows = $cursor->next )
  {
      print $rows[0]->select('foo'), "\n";
      print $rows[1]->select('bar'), "\n";
  }

DESCRIPTION

Objects in this class are used to return arrays of Alzabo::Runtime::Row objects when requested. The cursor does not preload objects but rather creates them on demand, which is much more efficient. For more details on the rational please see the RATIONALE FOR CURSORS section in Alzabo::Design.

INHERITS FROM

"Alzabo::Runtime::Cursor"

METHODS

next

Returns the next array of "Alzabo::Runtime::Row" objects or an empty list if no more are available.

If an individual row could not be fetched, then the array may contain some "undef" values. For outer joins, this is normal behavior, but for regular joins, this probably indicates a data error.

all_rows

This method fetches all the rows available from the current point onwards. This means that if there are five set of rows that will be returned when the object is created and you call "next()" twice, calling "all_rows()" after it will only return three sets.

The return value is an array of array references. Each of these references represents a single set of rows as they would be returned from the "next" method.

reset

Resets the cursor so that the next "next()" call will return the first row of the set.

count

Returns the number of rowsets returned by the cursor so far.

next_as_hash

Returns the next rows in a hash, where the hash keys are the table names and the hash values are the row object. If a table has been included in the join via an outer join, then it is only included in the hash if there is a row for that table.

AUTHOR

Dave Rolsky, <autarch@urth.org>

2022-06-14 perl v5.34.0