Class and one property is also a class or collection

Hi,

I have the following data that I put in an array.

ID---------Name-----Type---------NR--------De---------Cr
A001----Chris-------F66----------1111-----------------10
A001 ----Chris-------FACT-------1234------10
A001 ----Chris-------F66----------5678-----15
B002 ----Sarah------F58----------2222-------7
C003 ----Bill----------FACT--------3333-------5

To put it in an array I used this.

Please Login or Register  to view this content.

Now I'm trying to put everyting in classes.

The Class is called clsClient
And has the following properties:

Please Login or Register  to view this content.

But I'm stuck with the invoice properties cause I should use a different class.
For example clsInvoice with the following properties:

Please Login or Register  to view this content.

1) How can I add the clsInvoice as a property to clsClient cause it's not one invoice per client but there can be several invoices.
Do I need to create another class to hold all the invoices? Like a collection class?
(I have no experience with collection classes)

2) How can I loop through the array and fill the class correctly.
This code is not finished and definitely wrong :-/

Thanks in advance!

Greets

The simplest way would be to add a Collection object to the first class and then add the invoices to that.
I would also recommend reading through Patrick's article here.