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I send you a attach of my modified refint.c that

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works with a new policy  in cascade mode .

Please Read README.MAX .
I do not know if you are the author of refint.c ,
but if not please tell me who is .


Thank you ( excuse me for my bad english) .
Massimo Lambertini massimo.lambertini@everex.it
This commit is contained in:
Bruce Momjian
1999-05-10 15:12:29 +00:00
parent 9e4e33c996
commit d489fdfc7f
9 changed files with 424 additions and 156 deletions
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76
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Here are general trigger functions provided as workable examples
of using SPI and triggers. "General" means that functions may be
used for defining triggers for any tables but you have to specify
table/field names (as described below) while creating a trigger.
1. refint.c - functions for implementing referential integrity.
check_primary_key () is to used for foreign keys of a table.
You are to create trigger (BEFORE INSERT OR UPDATE) using this
function on a table referencing another table. You are to specify
as function arguments: triggered table column names which correspond
to foreign key, referenced table name and column names in referenced
table which correspond to primary/unique key.
You may create as many triggers as you need - one trigger for
one reference.
check_foreign_key () is to used for primary/unique keys of a table.
You are to create trigger (BEFORE DELETE OR UPDATE) using this
function on a table referenced by another table(s). You are to specify
as function arguments: number of references for which function has to
performe checking, action if referencing key found ('cascade' - to delete
corresponding foreign key, 'restrict' - to abort transaction if foreign keys
exist, 'setnull' - to set foreign key referencing primary/unique key
being deleted to null), triggered table column names which correspond
to primary/unique key, referencing table name and column names corresponding
to foreign key (, ... - as many referencing tables/keys as specified
by first argument).
Note, that NOT NULL constraint and unique index have to be defined by
youself.
There are examples in refint.example and regression tests
(sql/triggers.sql).
To CREATE FUNCTIONs use refint.sql (will be made by gmake from
refint.source).
# Excuse me for my bad english. Massimo Lambertini
#
#
# New check foreign key
#
I think that cascade mode is to be considered like that the operation over
main table is to be made also in referenced table .
When i Delete , i must delete from referenced table ,
but when i update , i update referenced table and not delete like unmodified refint.c .
I made a patch that when i update it check the type of modified key ( if is a text , char() i
added '') and then create a update query that do the right think .
For my point of view that policy is helpfull because i do not have in referenced table
loss of information .
In preprocessor subdir i have placed a little utility that from a SQL92 table definition,
it create all trigger for foreign key .
the schema that i use to analyze the problem is this
create table
A
( key int4 not null primary key ,...) ;
create table
REFERENCED_B
( key int 4 , ... ,
foreign key ( key ) references A --
);

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-- Note the syntax is strict because i have no time to write better perl filter.
--
-- [blank] is 1 blank
-- at the end of an interesting line must be a [,] or [--]
-- [ending] must be a , or --
--
-- foreign[blank]key[blank]([blank]keyname,..,keyname[blank])[blank]references[blank]table[blank][ending]
--
-- step1.e < example.sql | step2.pl > foreign_key_triggers.sql
--
-- step1.e is a simple program that UPPERCASE ALL . I know that is simple implementing in Perl
-- bu i haven't time
CREATE TABLE
gruppo
(
codice_gruppo int4 NOT NULL,
descrizione varchar(32) NOT NULL
primary key ( codice_gruppo )
) ;
--
-- fa_parte : Appartenenza di una Azienda Conatto o Cliente ad un certo GRUPPO
--
CREATE TABLE
fa_parte
(
codice_gruppo int4 NOT NULL,
codice_contatto int4 NOT NULL,
primary key ( codice_gruppo,codice_contatto ) ,
foreign key ( codice_gruppo ) references gruppo --
);

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#include <stdio.h>
char *strtoupper(char *string)
{
int i ;
for (i=0;i<strlen(string);i++)
{
string[i]=toupper(string[i]);
}
return string;
}
void main ( char argc , char **argv )
{
char str[250];
int sw = 0 ;
while ( fgets (str,240,stdin) )
{
if ( sw == 0 ) printf("%s",strtoupper(str));
}
}

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#!/usr/bin/perl
##
## MAIN
##
$table_name="";
$old_name="";
$references_table="";
$references_column="";
$is_create=0;
while ( <> )
{
chop;
$str=$_ ;
if ($is_create == 1) {
$table_name=$str;
$is_create=2;
}
if ( $str =~ /^CREATE TABLE/ ){
$is_create=1;
}
if ($is_create == 2) {
if ($str =~ /^FOREIGN KEY/){
($d1,$d2,$d3,$columns,$d4,$d5,$references_table,$d6) = split (/ /,$str,8);
#printf "Table $table_name $columns $references_table\n";
if ($table_name ne $old_name ){
printf "--\n-- Trigger for $table_name\n--\n\n";
}
foreach $i ( split(/,/ , $columns ) ){
print "CREATE INDEX I_$table_name";
print "_$i ON $table_name ( $i ) ;\n";
}
printf "\nCREATE TRIGGER T_P_$table_name";
printf "_$references_table BEFORE INSERT OR UPDATE ON $table_name FOR EACH ROW\n" ;
printf "EXECUTE PROCEDURE\n";
printf "check_primary_key(";
$val=0;
foreach $i ( split(/,/ , $columns ) ){
print "'$i',";
$val=$val+1 ;
}
print "'$references_table',";
$t=1;
foreach $i ( split(/,/,$columns ) ){
print "'$i'";
if ( $t < $val ) {
printf ",";
}
$t=$t+1;
}
print " );\n\n";
printf "CREATE TRIGGER T_F_D_$references_table";
printf "_$table_name BEFORE DELETE ON $references_table FOR EACH ROW\n" ;
printf "EXECUTE PROCEDURE\n";
printf "check_foreign_key(1,'cascade',";
$val=0;
foreach $i ( split(/,/ , $columns ) ){
print "'$i',";
$val=$val+1 ;
}
print "'$table_name',";
$t=1;
foreach $i ( split(/,/,$columns ) ){
print "'$i'";
if ( $t < $val ) {
printf ",";
}
$t=$t+1;
}
print " );\n\n";
printf "CREATE TRIGGER T_F_U_$references_table";
printf "_$table_name AFTER UPDATE ON $references_table FOR EACH ROW\n" ;
printf "EXECUTE PROCEDURE\n";
printf "check_foreign_key(1,'cascade',";
$val=0;
foreach $i ( split(/,/ , $columns ) ){
print "'$i',";
$val=$val+1 ;
}
print "'$table_name',";
$t=1;
foreach $i ( split(/,/,$columns ) ){
print "'$i'";
if ( $t < $val ) {
printf ",";
}
$t=$t+1;
}
print " );\n\n";
if ($table_name ne $old_name ){
printf "-- ********************************\n\n\n";
}
$old_name=$table_name ;
}
}
if ($str =~ /^\)\;/ ) {
$is_create = 0 ;
}
}