在 mysql 和 php 中实施定价计划的最简单方法是什么？

Question

I am working on a project, and I am trying to find a way to associate my pricing plans table with a customer.

id  name    description      price  days
1   Free    the free plan    0.00   0
2   Silver  the silver plan  49.99  365
3   Gold    the gold plan    99.99  365

My first thought was to add the plan id as foreign key to the customers table. But i also need to know when is the expire date (based on the purchase date and the days of the plan selected).

Answer 1

When attempting to do something like this, it is best to keep tables abstracted from each other.

user_pricing_plans  - the table name
pricing_plans_id - the id for the record you want to associate with a user
user_id   - the id of the user
date_expiration - the date the plan will expire
date_purchased - the date the plan was purchased

following an approach like this will allow you alter this table if needed to add extra information. you could also follow a similar approach in the future with another table.

the key to all of this is separating your concerns ( the data ) into separate containers.

Edit: to kind of hint at what I'm getting at about why separating the tables is a good idea, I added the date_purchased as a field in the user_pricing_plans table.

a dba I know once said that "mysql is not a place for developers - they try to create tables to work with their code. tables are meant to represent data. your code should be written to work with the data and the schemas that represent them - not the other way around"

Answer 2

I do not know why I can not add a comment to the best answer in the post.

As @Jonathon Hibbard points few years ago, there is another reason to separate the data between pricing plan and user model.

You used to have users who have one plan and choose another later, that is called, "history". To manage that, this third table is very important.

And in my opinion, more important, one thing is your pricing table, an another one is the final price you have with every client. Yo have knownledge people, close clients that you want "special" prices, this third table gives you the oportunity to set diferent prices for one plan with fixed price and a lot of other use cases.

Think about your main plan table like a product, the user is the client, and the third party as the ticket, with "temp pricing" aplied, ocassional discounts or whatever.