There is also the drawback that the
trigger has to do a 'select for update',
with all associated contention problems,
otherwise the effect of read-consistency
would allow a trigger to determine that a
parent existed when in fact it had been
deleted by an uncommitted transaction.
Jonathan Lewis
Host to The Co-Operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
Author of:
Practical Oracle 8i: Building Efficient Databases
See http://www.jlcomp.demon.co.uk/book_rev.html
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-----Original Message-----
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
Date: 27 August 2001 18:15
You can only FK to field(s) that are unique or primary key
constraints.
if col1 is unique, you can put a unique constraint on it and then FK
to it from the child.
your only other choice is to do FK checkign via triggers(i did it for
distributed databases, where parents were on one db and children were
on other, efficient NO but it was a requirement).
joe
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