Re: Handling Null or Undef values in DBI (and things of those nature)...

I hope this info can help you with your 2nd
question.

Off the top of my head there are aleast 3 ways
to check the table before you insert a new record.

way one) would be to define a unique constraint
on this table in the DBMS. This will prevent any
insertion of a record that is a duplicate.

way two) would be to define a before insert trigger
and have this trigger check for a duplicate.

way three) execute the query select count(*) into n from ...
and if n > 0 then the record exist.

--
Its like a dog that can sing and dance.
It's remarkable because it can do it.
Not that it can do it well.

Comment on Re: Handling Null or Undef values in DBI (and things of those nature)...

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Re: Re: Handling Null or Undef values in DBI (and things of those nature)... by data67 (Monk) on Jan 08, 2002 at 05:10 UTC
Can you please give me an example or two on your seggestions. As far as my first question i got it done by doing this `while (@row = $sth->fetchrow_array) { foreach (@$row) { $_ = '' unless defined; ### HANDLE NULL FIELDS } }` [download]	[reply] [d/l]
Re: Re: Handling Null or Undef values in DBI (and things of those nature)... by rbc (Curate) on Jan 09, 2002 at 02:28 UTC
Find an SQL manual or on-line doc. and look up the ALTER TABLE and CREATE TRIGGER commands. They do a much better job than I could :) -- Its like a dog that can sing and dance. It's remarkable because it can do it. Not that it can do it well.	[reply]