#! /bin/sh

# You first run findoidjoins on the template1 database, and send that
# output into this file to generate a list of SQL statements.

# NOTE: any field that findoidjoins thinks joins to more than one table
# will NOT be checked by the output of this script.  You should be
# suspicious of multiple entries in findoidjoins' output.

# Caution: you may need to use GNU awk.
AWK=${AWK:-awk}

trap "rm -f /tmp/$$ /tmp/$$a /tmp/$$b" 0 1 2 3 15

# Read input
cat "$@" >/tmp/$$

# Look for fields with multiple references.
cat /tmp/$$ | cut -d' ' -f2 | sort | uniq -d >/tmp/$$a
if [ -s /tmp/$$a ] ; then
	echo "Ignoring these fields that link to multiple tables:" 1>&2
	cat /tmp/$$a 1>&2
fi

# Get the non-multiply-referenced fields.
cat /tmp/$$ | while read LINE
do
	set -- $LINE
	grep "$2" /tmp/$$a >/dev/null 2>&1 || echo $LINE
done >/tmp/$$b

# Generate the output.
cat /tmp/$$b |
$AWK -F'[ \.]' '\
	BEGIN \
	{
		printf "\
--\n\
-- This is created by pgsql/contrib/findoidjoins/make_oidjoin_check\n\
--\n";
	}
	{
		printf "\
SELECT	oid, %s.%s \n\
FROM	%s \n\
WHERE	%s.%s != 0 AND \n\
	NOT EXISTS(SELECT * FROM %s AS t1 WHERE t1.oid = %s.%s);\n",
	$2, $3, $2,
	$2, $3,
	$5, $2, $3;
	}'

exit 0