We have 3 stores, and the requirement is when a customers registers on any one of the 3 stores, and if the customer again registers on any one of the other 2 stores, we want to have a check that if the customer is already registered with any one of the other 2 stores so that on new customer registration page we can display customer the message that if he has registration on store1 then he can use the same userid/password for this store too.
This way we will be able to minimise the no. of users because the same id can be used across all the stores, and also it will solve the issue when instead of having any user id, which the user creates, you are using email id for user id, otherwise incase of using email id for user id field, the user will need to create 3 email id's for 3 stores. We can have a UserStoreAssoc table which will have userid & product store id mapping, so that we can check if the user has already registered with any other stores. During user registration we can create a record in this table. - Abdullah
