basic database design table on rails

Question

I am confuse on a concept. I am doing this on rails.

Is that Entity set equal to a table in the database?

Is that Relationship set equal to a table in the database?

Let say we have Entity set "USER" and Entity set "POST" and Entity set "COMMENT"

User- can post many posts and comments as they want
Post- belong to users
Comments-belong to posts ,users, so comment is weak entity.

SCHEMA
======
USER
-id
-name
POST
-id
-user_id(FK)
-comment_id (FK)
COMMENT
-id
-user_id (FK)
-post_id (FK)

so USER,POST,COMMENT are tables I think.

And what else is a table? And do I need a table for the relationship??

You should really read [the docs](http://guides.rubyonrails.org/association_basics.html). Sometimes you need a table for the relationship and sometimes you don't. It depends on how you declare the relationship in the model. — sosborn, Oct 02 '12 at 03:31

score 1 · Accepted Answer · answered Oct 02 '12 at 03:34

1

yes, they are tables but them should be always in a plural way. So you can have User, Post, Comment as models and Users, Posts, Comments as tables. And then yours models are related with their own tables

answered Oct 02 '12 at 03:34

Alexander Giraldo

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score 0 · Answer 2 · edited May 23 '17 at 12:12

0

Given the data you do, start with the generators (add any additional needed fields, see rails generates model field:type, what are the options for field:type?):

rails generate model user name:string
rails generate model post user:references
rails generate model comment user:references post:references

edited May 23 '17 at 12:12

Community

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1

answered Oct 02 '12 at 09:13

rewritten

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basic database design table on rails

2 Answers2