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

    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>