fireproofsocks
Defining Ecto Schemas (PostGres) to use NOT NULL in column definitions
I’m working on defining a simple Ecto schema for a table (in PostGres), but I don’t see where I can define a column as NOT NULL. Consider the following schema:
schema "addresses" do
field :name, :string, size: 100
field :company, :string, size: 100
field :street1, :string, size: 250
field :street2, :string, size: 250
field :city, :string, size: 100
field :state, :string, size: 2
field :zip, :string, size: 32
field :zip4, :string, size: 4 # NOT NULL?
timestamps()
end
I would prefer that the zip4 column can never be null… is there a way to do this? I don’t see it referenced on https://hexdocs.pm/ecto/Ecto.Schema.html
Thanks!
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OvermindDL1
You don’t specify if a column can be null or not in the schema, you do it in the migration (by setting , null: false). 
Remember, Ecto does not duplicate checks that the database already does (as many are just impossible to know ahead of time, although this one could be, it’s good to keep consistency).
jeremyjh
This is correct but it is possible to enforce this constraint in your changeset function, which will yield a nice Changeset error rather than an exception.You can use validate_required in your changeset function. I’d still set null: false in the migration.
jeremyjh
So far as I know, the “right” way to setup the changeset to make a field be required is to use the Changeset function validate_required. That is how we do it. If I take the validate_required function out of my Changeset and leave the field blank, I end up with a Postgrex exception along the lines:
** (exit) an exception was raised:
** (Postgrex.Error) ERROR 23502 (not_null_violation): null value in column "title" violates not-null constraint
table: listings
column: title
I don’t have any code I can share at the moment.
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