我是MySQL的初学者。我有这段代码,我想解释一下,既然定义了$conn和$db,函数是如何知道要使用哪个数据库的?$conn = mysql_connect("localhost","primeb5_mysql","***");$query= "SELECT * FROM lesson3";
$result = m
dbUsername,$dbPassword,$dbName); die("Failed to connect with MySQLmysqli_connect_error()); $this->connect = $con; }如何使用this.This为新文件调用新的数据库连接是我的function.php。我现在想把这叫