Thread

1. RE: RI and PARSER (was: Re: [HACKERS] RI status report #1)

   Jackson, DeJuan <djackson@cpsgroup.com> — 1999-09-29T16:31:58Z

   What does PENDANT imply/mean in terms of RI?  I could figure out all of the
   other syntax.
   
   > -----Original Message-----
   > From:	wieck@debis.com [SMTP:wieck@debis.com]
   > Sent:	Wednesday, September 29, 1999 9:03 AM
   > To:	lockhart@alumni.caltech.edu
   > Cc:	wieck@debis.com; tgl@sss.pgh.pa.us; hackers@postgreSQL.org
   > Subject:	Re: RI and PARSER (was: Re: [HACKERS] RI status report #1)
   > 
   > Thomas Lockhart wrote:
   > 
   > >
   > > > > >       CONSTRAINTS
   > > > > >       DEFERRABLE
   > > > > >       DEFERRED
   > > > > >       IMMEDIATE
   > > > > >       INITIALLY
   > > > > >       PENDANT
   > > > > >       RESTRICT
   > > >     O.K.  - I was able to add them all to ColId without conflicts
   > > >     for now.  Let's see what happens after adding the syntax  for
   > > >     CREATE CONSTRAINT TRIGGER.
   > >
   > > Right. Anything which causes trouble can be demoted to ColLabel.
   > >
   > > >     I'm  not  sure which of them are SQL92 or SQL3, at least they
   > > >     are all SQL3 "reserved" words according to the SQL3 draft.
   > >
   > > According to my Date and Darwen (which is mostly SQL92), all of these
   > > except "PENDANT" are SQL92 reserved words. PENDANT is not mentioned,
   > > so is presumably an SQL3-ism.
   > >
   > > Do you want me to update syntax.sgml?
   > 
   >     Please  be so kind. CREATE CONSTRAINT TRIGGER did not mess up
   >     anything, so all these new reserved words appear in ColId and
   >     are still available.
   > 
   > 
   > Jan
   > 
   > --
   > 
   > #======================================================================#
   > # It's easier to get forgiveness for being wrong than for being right. #
   > # Let's break this rule - forgive me.                                  #
   > #========================================= wieck@debis.com (Jan Wieck) #
   > 
   > 
   > 
   > ************
   
   

2. Re: RI and PARSER (was: Re: [HACKERS] RI status report #1)

   Jan Wieck <wieck@debis.com> — 1999-09-29T17:25:32Z

   >
   > What does PENDANT imply/mean in terms of RI?  I could figure out all of the
   > other syntax.
   
       As far as I understood it:
   
         CREATE TABLE t1 (a1 integer PRIMARY KEY NOT NULL, b1 text);
   
         CREATE TABLE t2 (a2 integer NOT NULL, b2 text,
                          CONSTRAINT check_a2
                            FOREIGN KEY (a2)
                            REFERENCES t1 (a1)
                            PENDANT
                            ON DELETE CASCADE
                            ON UPDATE CASCADE
                            INITIALLY DEFERRED);
   
       This  setup requires, that for each key in t1.a1 at least one
       reference  from  t2.a2  MUST  exist.  So  this  is  a  cyclic
       integrity check.  I'm not sure if removing the last reference
       automatically removes the PK row from t1 or if it  raises  an
       error. Can someone clearify here?
   
   
   Jan
   
   --
   
   #======================================================================#
   # It's easier to get forgiveness for being wrong than for being right. #
   # Let's break this rule - forgive me.                                  #
   #========================================= wieck@debis.com (Jan Wieck) #