On 2012-10-22 15:16:47 +0800, Tim Bowden wrote:
> Is it possible, and if so, how can I set the number of placeholders in a
> prepared statement at runtime?
>
> IE, given something like:
>
> my $sth = $dbh->prepare("INSERT INTO $table ($fields) VALUES (?,?,?));
>
> which is fine if I know how many fields I'm inserting into, but what if
> I don't know till runtime how many fields? How can I put the (?,?,?)
> into a variable and have it recognised as placeholders?
You could do something like
my $placeholders = '(?,?,?)';
my $sth = $dbh->prepare("INSERT INTO $table ($fields) VALUES $placeholders");
but I guess you thought of that and your question is really
How can I get $placeholders from $fields?
If I have a variable number of fields I usually have them in array, not
a scalar, so I can just count the members:
$fields = join(',', @fields);
$placeholders = '(' . join(',', map('?', @fields)) . ')';
my $sth = $dbh->prepare("INSERT INTO $table ($fields) VALUES $placeholders");
(and then you can get rid of $fields and $placeholders and do it all in
a single line)
hp
--
_ | Peter J. Holzer | Auf jedem Computer sollte der Satz Ludwigs II
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