Question

I need a table where to keep imported contacts (emails) by users, something like an address book.

Now the table look like this: imported_contacts: id, user_id, email, etc....

I’m thinking to create a table imported_contacts: id, email, etc and another table user_contacts: id, user_id, imported_contact_id, date, etc to avoid keeping duplicate emails in table imported_contacts. So with the new idea I keep in imported_contacts all imported email in the other table user_contacts I keep relationship between users and imported_contacts.

Is this a useful idea?

Answer 1

If I understand this correctly, if two users add the same contact, it is stored on just one row in the table, and both the users see the same row.

I see two problems with this:

1. if one user updates the email (or any other information of the contact), the information will also appear updated to the second user, and the initial information of the second user would be lost.

2. I don’t know if you store other fields besides email, but if you do, you must consider that they might have different values, depending on the user; for example, if you store the name of the contact, the first user might write the contact’s full name, and the second user, the high-school nickname.

Now it really depends on what this application is used for. If it’s just for the internal use of one company, their client database for example, then it might be useful to have any changes propagate to all the users, so problem no. 1 would not really be a problem. But otherwise it wouldn’t be ok.