Ecto Many-To-Many insertion with additional attributes in association table, need help with approach

[mythicalprogrammer]

Welcome to Elixir Forum.

This works for while inserting one student, but when inserting next record the Teacher would exist already and there is a chance it will insert multiple records for the same Teacher.

You just need to check for this. Either a database constraint for uniqueness of combination or in your elixir code.

For many to many with existing record I believe you need to explicitly use join table and use cast_assoc put_assoc. This imply that you need to code out explicitly the join table as a schema. I know you don’t have to in other cases but so far in my experience I’ve made schema for all my join tables since I often use one of the two tables as lookup table.

You can see my thread I made here:

Insert many to many ecto was harder because lack of info

It’s a bit of ranting. I just hope this is constructive. Anyway the problem: I have a perfumes table which have a many to many relationship with companies table. So there is a join table perfume_company_joins (I know I’m very good at naming). Anyway, the companies table is mostly static. It’s like a look up table. Users are able to submit a request to add a new perfume, sign this form html template and add how many company that was involve in building the perfume. The problem is I couldn’t …