Grabbing orders from a different database

I am very new to ERPNext and I have search the forums and haven’t (yet) found an answer.

We have a custom PHP app that use a MYSQL database. When an order is placed it creates the order with an ID number, the selected products/services and have a status switch as well.

Is there a way that I have ERPNext fetch the orders and push them to a sales order or invoice?

You could create a CSV file from your custom PHP app, and then do a scheduled import of that file on a cronjob every 1m or something