I am creating a course booking system. Having database experience but not with mySql i have been reading that mySql does not support foreign keys, which was bit of a surprise for a database. How can this be implemented in mySql.
Another question which I am unable to answer is how do you ensure that a query that asks "what customer have taken what courses in the last 12 months" returns the customers and courses if you have deleted the course months ago.
I am not convinced that you cannot have some sort of archiving. From what I know a lot of medium to large sized companies use mySql and I can't imagine them staying in business long not being abe to run reports for marketing purposes. These are basic queries that you would want ay db to be able to perform.
I wasn't very clear with what i was trying to achieve. On my ERD I have a BOOKING LINE table which will contain all booking info of courses for a particular company. I don't have a pk:fk relationship with the COURSE table. This has been achieved through COURSE VENUE, VENUE, tables. I think I am right in saying that a course can be deleted from the COURSE table but the BOOKING LINE table will still contain all the courses a particular customer went on. This table will grow until it has to be archived off. So queries could be run of the BOOKING LINE table.