NAME

Genezzo::Plan::QueryRewrite - Perform checks on relational algebra representation

SYNOPSIS

use Genezzo::Plan::QueryRewrite;

DESCRIPTION

Rewrite relational algebra.

ARGUMENTS

FUNCTIONS

QueryRewrite

Perform typechecking on a relational algebra, and add type information to the tree

TableCheck

Check table references in the relational algebra, and provide type information.

ColumnCheck

Resolve each column reference in the relational algebra back to some base table.

EXPORT

LIMITATIONS

TODO

check for function existance in GenDBI and main namespaces

update pod

need to handle FROM clause subqueries -- some tricky column type issues.

check bool_op - AND purity if no OR's.

check relational operator (comp_op, relop)

handle ddl/dml (create, insert, delete etc with embedded queries) by checking for query_block info -- look for hash with 'query_block' before attempting table/col resolution. Need special type checking for these functions.

refactor to common TreeWalker

_process_name_pieces: quoted string/case-insensitivity

handle all pseudo cols

most value expression stuff needs to migrate to XEval

AUTHOR

Jeffrey I. Cohen, jcohen@genezzo.com

SEE ALSO

perl(1).

Copyright (c) 2005 Jeffrey I Cohen. All rights reserved.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

Address bug reports and comments to: jcohen@genezzo.com

For more information, please visit the Genezzo homepage at http://www.genezzo.com