#28 exempt departments from sale level promotions

[Iain Sinclair]

A suggested enhancement.

It should be possible to specify departments whose
items are not to be included in sale level promotions.
This is typically necessary for low margin, low cost items.

To accomplish this:

1. add new column to the DEPARTMENT table:

SALEMOD_EXCLUDE

2. Fix up the data.Department DAO class (it has a bug
too) and add the new column.

3. Mod the relations() method of data.Item to read the
department record, to get the department_no and the
value of

the salemod_exclude flag and keep it avaliable for later
use.

4. Mod the PosContext.applySaleMod() method to
exclude items with the flag set to true.

5. look at AmountDiscount and search for the
word "hack". This bit of code should be fixed up too.

Note that the value stored in the item.dept column
should be the department_id, not department_no.

I think that is all.

I'm thinking that this could be done at the item level
too. An item is excluded from sale level promotions if it
is excluded at either the item or department level.

Then there is the question of whether a department
level exclusion should be over-rideable by individual
items.