mysql porting v2

[syjer]

Some additional task related to the mysql support:

• re enable disabled test (Migration?) (seems to be an issue with the transactiontemplate (with hsqldb, check with others too))
• check "check constraints" :) (emulate them with triggers?)

[syjer]

existing check constraints:

alter table promo_code add constraint "check_promo_code_min_length" check (char_length(promo_code) >= 7);
alter table promo_code add constraint "check_discount_type" check (discount_type = 'FIXED_AMOUNT' OR discount_type = 'PERCENTAGE');
alter table promo_code add constraint "check_discount_amount" check (
CASE
    WHEN discount_type = 'FIXED_AMOUNT' THEN discount_amount >= 0
    WHEN discount_type = 'PERCENTAGE' THEN discount_amount >= 0 and discount_amount <= 100
END);

[syjer]

The constraint has been ported as a code in the service layer.

[syjer]

migration test has been reenabled :)