Question

I have a form where there are preferences for a hotel customer. There are a lot of preferences, for instance, for the “Drink” category, there is “coca”, “wine”, “whiskey”. Customers can make multiple selection, for example, selecting both wine and coca for Drink. I have a table named “customer_preferences” to store their preferences in postgresql. The table will consist of the ID of the customer as primary key and columns like “Drinks” and “Leisure”. Now when a customer has selected “coca” and “wine” for drink, how can I store both these values? Also I am planning to use the database for data mining. My question is how can I store multiple values of preferences and the corresponding insert statement?
Thank you.

Answer 1

You’ll have CUSTOMER and PREFERENCE tables, with a one-to-many relationship between them.

You’ll have a single transaction that looks like this:

1. Insert the CUSTOMER parent record.
2. Get the generated primary key for the new CUSTOMER record.
3. INSERT one record for each PREFERENCE using the primary key of the new CUSTOMER record as the foreign key.

So you’ll have (n+1) INSERTs and one SELECT for a single CUSTOMER record and n PREFERENCE records.