For the DBI case, the correct answer is definitely placeholders.

However, in the general case, consider Interpolation. It's pretty nifty. It lets you define "arbitrary interpolation semantics".

From its man page: 

For example, you can say

    use Interpolation 
        money     => \&commify_with_dollar_sign,
        E         => 'eval',
        placename => 'ucwords';

And then you can write these:

    print "3 + 4 = $E{3+4}";
    # Prints  ``3 + 4 = 7''

    $SALARY = 57500;
    print "The salary is $money{$SALARY}";
    # Prints  ``The salary is $57,500.00''

[download]
For your need, you could use this: 
use vars qw/$dbh/;
use DBI;
$dbh = DBI->connect('baz', 'foo', 'bar', 'Oracle');

use Interpolation quoteit => sub { $dbh->quote(@_) };
print "select * from foo where bar = $quoteit{baz}";

[download]
Which is quite handy. Still, in your particular case, placeholders are better.

In reply to Re: Calling a method within a double-quoted string? by btrott
in thread Calling a method within a double-quoted string? by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.