NAME

Persist::Join - Data abstraction representing the joining of multiple tables

SYNOPSIS

  use Persist::Source;

  # For joins where a FOREIGN KEY may be used to perform the join implicitly
  $source = new Persist::Source(...);
  $join = $source->join([ 'Folks', 'Favorites' ], 
                        [ undef, "color = 'Blue'" ]);

  print "Folks with whose favorite color is Blue:\n";
  while ($join->next) {
	  print $join->name, "\n";
  }

  # For explicit joins where there is no FOREIGN KEY, or implicit joining is
  # undesirable
  $join = $source->explicit_join(
                        { O => 'Folks', A => 'Favorites' },
                        [ "O.fid = A.fid" ], "A.color = 'Blue'");

DESCRIPTION

This abstraction allows for easy access to multiple joined tables. It is an extension of Persist::Tabular and most of the functionality available is documented there.

$join = $source->join($tables, $filters)

See Persist::Source for details.

$join = $source->explicit_join($tables, $on_exprs, $filter)

See Persist::Source for details.

SEE ALSO

Persist::Tabular, Persist::Source

AUTHOR

Andrew Sterling Hanenkamp, <hanenkamp@users.sourceforge.net>

COPYRIGHT AND LICENSE

Copyright (c) 2003, Andrew Sterling Hanenkamp
All rights reserved.

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    notice, this list of conditions and the following disclaimer in 
    the documentation and/or other materials provided with the 
    distribution.
  * Neither the name of the Contentment nor the names of its 
    contributors may be used to endorse or promote products derived 
    from this software without specific prior written permission.

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