Is the leading colon for parameter names passed to PDOStatement::bindParam() optional?

Question

When passing named parameters of the form :name to PDOStatement::bindParam(), it seems to work whether or not the leading colon is used.

i.e. either this:

$statement->bindParam(':name', $var); 

or this:

$statement->bindParam('name', $var); 

seems to work.

Here's the documentation for PDOStatement::bindParam()

parameter

Parameter identifier. For a prepared statement using named placeholders, this will be a parameter name of the form :name. For a prepared statement using question mark placeholders, this will be the 1-indexed position of the parameter.

Does this mean the colon can be left off?

Answer 1

No, since the documentation doesn't mention this I think it's safe to assume that this behaviour isn't officially supported and shouldn't be relied upon.

However, it does actually happen to work (in PHP 5.3.24 at least) - internally a colon will be added to the parameter if it's missing (see ext/pdo/pdo_stmt.c:363 in the PHP 5.3.24 source code).