Re: Saving array reference

DBI::st appears to re-use internally an arrayref (I just got bitten by this today). You will have to store the record yourself:


my $first = undef;

while (my $record = $sth->fetchrow_arrayref) {
  unless (defined $first) { @{$first} = @{$record} }
  # other stuff
}
[download]

..although I'm unclear as to why you can't just stop retrieving records after the first, or why you can't just use a 'limit 1' clause in your SQL.

Also my DBI doesn't define a fetch method on statement handles, only fetchrow_* and fetchall_*, so you may need to re-jig my example.

Update: jZed++ for pointing out fetch is an alias for fetchrow_arrayref. Thanks, I've managed to miss that in every reading of perldoc DBI.

Comment on Re: Saving array reference Download Code

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Re^2: Saving array reference by jZed (Prior) on Apr 30, 2005 at 20:28 UTC
fetch() is a synonym for fetchrow_arrayref().	[reply]
Re^2: Saving array reference by Errto (Vicar) on May 01, 2005 at 01:34 UTC
Good suggestions. Just two minor points: first, in fairness to the DBI developers, the fact that `fetchrow_arrayref` reuses the same reference isn't just "internal", but is actually documented in the DBI docs: Note that the same array reference is returned for each fetch, so don’t store the reference and then use it after a later fetch. Second, the 'limit n' syntax isn't used across all databases, though for anyone on MySQL that's certainly a good suggestion. But Oracle, for example, doesn't have it.	[reply] [d/l]
Re^2: Saving array reference by mhearse (Chaplain) on Apr 30, 2005 at 20:18 UTC
Thanks, works great. You right though, I guess I could just do another query (strictly for the first match). Just wasn't thinking that way at the time. My thought was to save the first match for later use.	[reply]