The PDO_MYSQL Data Source Name (DSN) is composed of the following elements:
DSN prefix
The DSN prefix is mysql: .
host
The hostname on which the database server resides.
port
The port number where the database server is listening.
dbname
The name of the database.
unix_socket
The MySQL Unix socket (shouldn't be used with host or port).

charset
The character set. See the character set concepts documentation for more information.