将PDO与现有的MYSQL / PHP应用程序集成

Question

I am building some new additions to an existing WebApp. The old code was written using mysql functions. Changing the entire application to use PDO would be a VERY man-hour-intense thing to do. However, for all new code, I'd like to begin using PDO.

Are there any concerns I need to be aware of for using PDO within an existing application that does NOT use PDO to interface with the database? It's no problem to connect to the DB using both/either of these options at the same time when a page is loaded, correct?

While I'm at it - I am interested to know how big the need is to close a PDO connection after a page loads - or is it fine to leave the connection open?

Thanks all.

Answer 1

There's no need to close any type of database connection when a page finishes loading - PHP always does this for you (unless you make the mistake of enabling persistent connections).

However, if you use PDO AND mysql_ in the same page, connecting to the same database, it will consume twice as many connections (while the page is executing) on the server. This may or may not be a problem.

Personally I would recommend that you remain consistent within the application if you don't want to refactor it to use PDO throughout.