How Does Primary Key (primarykey) Work? Can Only Use Once?

I want to know if this primary key behavior is unique to Access or if it is THE WAY that all industry-standard primary keys work. Thus, I hope not to get too messed up on my SQL Server 2005 project--or any other SQL project.

In Access, I set up a table 'tbl_Gen_Admin_sto' to store general administration expenses. This is a budget. So, there can be at most one entry per budget_year / cost_center / account_number / month. If there are two or more entries, the data is messed up, something is wrong.

Therefore, I defined a muliple-field primary key for tbl_Gen_Admin_sto. If I make a programming mistake and enter data multiple times, the primary key feature will stop my program from entering the same data multiple times.

As I often do, I copy the data into another table, in this case tbl_Gen_Admin_tmp for manipulation in a form. (I.e., I connect a form to tbl_Gen_Admin_tmp.) The tmp version is a pivoted version of the sto table. So, in sto, I have one amount field for each month. In tmp, I have no month field, but do have one amount field for every month of the year (12 amount fields).

The transfer of data to tmp went fine. The user adds, changes, and deletes records in tmp through the form. When the user is done and wants to save the changes (and not discard changes), my program deletes the selected records from sto, then inserts the records from tmp.

But lo! Access was not accepting the new records because (error message) "key violations". The delete went fine. But the insert would not take.

I deleted the multiple-field primary key index in sto. Then I created a multiple-field regular index with no duplicates allowed. Now, sto accepts the insert.

I thought that when I deleted the records, the primary key field is gone--zzzzpft! But aparently Access is keeping track of all primary keys. Even though I deleted the record, for all eternity I will never ever be able to re-insert with the same primary key.

Here is where I need your help: Am I going to run into this same primary key behavior in SQL Server 2005? If so, is it because I have encountered the fundamental definition of primary key?

(I hope you don't beat me up too much for abusing primary keys.)