Sorting DatabaseTables by FK Constraints

If you have a simple schema where there are three tables Table A, Table B, and Table C, and

Table A has a FK constraint on Table B
Table B has a FK constraint on Table C

there should only be (theoreticaly) one correct path to insert records into this schema. You must insert records into Table C, then Table B, then Table A, not in any other order!

I want to make sure that this statement is generally correct.

I've written my own algorithm (I made my Table object in Java implement Comparable for those Java savvy folks) but my sorted Lists are not always correct. I've determined that given a List of Table objects there are many correct "sorted" results and I end up with localized sorted sections but my global sorted list is sometimes incorrect (and sometimes it's correct.)