Question

I have been able to make 2 ActiveRecord tables, Profile and Bot. I have been unable to figure out how to link them properly.

There are thousands of Profiles with columns username, gender. A handful of Bots with columns botname, level

When a bot visits a profile two pieces of info need to be recorded. visited and response should be updated for that specific bot. visited is a boolean that will indicate that one particular bot has visited that one particular profile. the response is a string, again like the visited this is a response for one particular bot that was sent by one particular profile. I am thinking I need a 3rd table that joins these two tables.

I need to keep a record of every profile that every bot visits and the response that happens when it visits.

How can I create this relationship and how can I set/update the columns?

Thanks

Answer 1

I’m not completely certain of your requirements, so I will restate them:

1. Table Profile: id, username, gender (note that I changed the table names to singular)
2. Table Bot: id, botname, level
3. The “bots” somehow “visit” profiles. You need to track when a bot has visited a profile.
4. When a bot visits a profile, a “response” string is generated and that response string needs to be preserved. I’m assuming it needs to be preserved with the record of the visit.

I think your instincts about a join table are good. I don’t think a boolean “visited” column works, however, because if you have a record of a visit, that’s an indication that the profile was visited. If the record doesn’t exist, then it wasn’t visited.

Given this, I think your tables look like this:

profile 
---------
profile_id integer autoincrement
username varchar(255)
gender ...

bot
---------
bot_id integer autoincrement
name varchar(255)
level ...

visit
---------
visit_id integer autoincrement
bot_id integer
profile_id integer
visit_time datetime
response varchar(255)

To maintain the integrity of your data, you’ll want to set up foreign key constraints between this visit table and your profile and bot tables.

alter table visit
    add constraint visit_profile_profile_id_fk 
    foreign key (profile_id) 
    references profile (profile_id);

alter table visit
    add constraint visit_bot_bot_id_fk 
    foreign key (bot_id) 
    references profile (bot_id);

You’ll need to decide if it’s “legal” for a given bot to visit a particular profile more than once. If it’s not, you should put a unique constraint on the combination of profile_id and bot_id in the visit table, and catch the duplicate key errors when your DBMS throws them at you (or otherwise handle dupes.)

I hope that helps.