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Re: Antw: many-many mapping between unique tables

From: KuroiNeko <evpopkov(at)carrier(dot)kiev(dot)ua>
To: pgsql-sql(at)postgresql(dot)org
Subject: Re: Antw: many-many mapping between unique tables
Date: 2000-10-16 15:14:27
Message-ID: 39EB1B53.nail1L21P304T@ed.ed (view raw or flat)
Thread:
Lists: pgsql-sql
> > I am facing a problem in mapping between two tables containing unique
> > entries
> >
> Then you need a  third table T12 with columns x and  y, that contains one
> row for each
> mapping of a x(i) with a y(j).

 That's it.  Normalize it. Relation T12  may also require the  third field,
`direction', to specify whether  this is T1 -> T2 or T2  -> T1. In general,
it'd be much better to re-design data layout.


--

 Well I tried to be meek
  And I have tried to be mild
 But I spat like a woman
  And I sulked like a child
 I have lived behind the walls
  That have made me alone
 Striven for peace
  Which I never have known

 Dire Straits, Brothers In Arms, The Man's Too Strong (Knopfler)


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