Is the Leading Colon for Parameter Names in PDOStatement::bindParam() Really Optional?

PDOStatement::bindParam() allows you to specify named parameters in your queries using placeholders such as :name. The documentation states that the parameter identifier for named placeholders should use the format :name. However, there have been observations that both :name and name can be used seemingly without any issues.

The Documentation and Supported Functionality

The PDOStatement::bindParam() documentation explicitly mentions using the colon prefix for named parameters (:name). This suggests that not using the colon is not officially supported.

Internal PHP Behavior

Despite the documentation, PHP internally adds a colon to parameter names if it's missing. This behavior can be observed in the PHP source code (ext/pdo/pdo_stmt.c:363). This means that when you use name without a colon, PHP will automatically add it.

Reliability and Recommendations

While this internal behavior is convenient, it's important to note that it's not supported by the official documentation. Therefore, it's not advisable to rely on this behavior and it's recommended to always use the colon prefix for named parameters when using PDOStatement::bindParam().