What is the difference between MySQL_connect and MySQL_pconnect?

Mysql_connect:

1. It opens a new connection to the database.
2. Every time you need to open and close database connection, depending on the request.
3. Opens page every time when it loaded.

Mysql_pconnect:

1. In Mysql_pconnect, "p" stands for persistent connection so it opens the persistent connection.
2. the database connection can not be closed.
3. it is more useful if your site has more traffic because there is no need to open and close connection frequently and every time when page is loaded.