Best way to store Master-Detail Data

Hi.

I wan to to know if someone can recommend me the best way to store
header and detail data
in the same function.

For example:

I have a table for purchase orders headers and a table for the detail
then i want to record
the header and detail under the same function to make sure that both
header and detail
are committed or not.

What i usually do is create a function with such as parameters as fields
in the header table and
after that, i add a same data type parameter for each field in the
detail but as an array.

In the function, i insert the header data, after that i use a loop on
the first array parameter,
how each array parameter has the same length, i use the ordinal position
to insert the lines.