# *********************************************************************
#  Written by and copyright Carlo Strozzi <carlos@linux.it>.
#
#  depend.txt: help text
#  Copyright (C) 2001 Carlo Strozzi <carlos@linux.it>
#
#  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
#  (at your option) 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., 675 Mass Ave, Cambridge, MA 02139, USA.
#
# *********************************************************************

                     NoSQL operator: depend

Assess functional dependency between two table columns.

Usage: depend [options] column_1 column_2

Options:
    --help (-h)
      Print this help info.

Notes:

Takes two column names and an input table and tries to work-out
whether there is a so called ``functional dependency'' between
the two. The second column is said to be functionally-dependent
on the first column when for each value in the former there is
only one value in the latter.

If column_2 is found to be functionally-dependent upon column_1,
then 'true' is printed to STDOUT and a return-code 0 is returned.
Otherwise the return-code is 1 and 'false' is printed.

The higher the number of records in the input table, the more
reliable the test is.

$Id$
