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Re: Devel::Declare type syntactic sugar for DBI select bind_col param

by moritz (Cardinal)
on Sep 30, 2012 at 14:45 UTC ( #996508=note: print w/replies, xml ) Need Help??

in reply to Devel::Declare type syntactic sugar for DBI select bind_col param

But my thinking isn't clear, any ideas?

I guess you are looking for feedback on the design, not the implementation. So here are some thoughts:

  • If stuff is bound to variable $email, the variable should appear like that in the select statement
  • Interpolation of variables should probably still be possible, so you need some syntax beyond just the variable name to make it clear which variables are bind variables and which ones are interpolated
  • SQL column names and column expressions are not confined to Perl identifiers, so you need some (optional) syntax for aliasing non-perl-identifier column descriptions to Perl variables

Given these constraints, I'd propose something along the lines of

$dbh->SELECT(':$name, :$email, :$duration(from - to) FROM table WHERE +duration > $min_duration' { say "$name <$email> has spent $duration days here"; }

Which would desugar to something like

$dbh->prepare('SELECT name, email, from - to AS duration FROM table WH +ERE duration > ?'); $dbh->bind_columns(\my ($name, $email, $duration); $dbh->execute($min_duration); while ($sth->fetch) { say "$name <$email> has spent $duration days here"; }

Maybe you also want to add another syntax for interpolating variables that are piped through $dbh->quote_identifer instead of placeholders, for when you need to interpolate the table name.

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marioroy just logged in to say that MCE::Hobo has passed testing and therefore will continue to run like threads but have managed capabilities similar to Parallel:: ForkManager. It allows multiple managed instances to run simultaneously. Zero limitations.
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