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elixirphoenix-frameworkecto

How do you set a default value for a decimal column in an Ecto migration?

I tried doing the following:

add :balance, :decimal, default: 0.0
add :balance, :decimal, default: "0.0"
add :balance, :decimal, default: Decimal.new("0.0")

The first 2 don't work at all as newly-created records still return nil if I don't explicitly pass a value.

The 3rd one returns this error:

** (ArgumentError) unknown default #Decimal<0.0> for type :decimal. :default may be a string, number, boolean, list of strings, list of integers, map (when type is Map), or a fragment(...)

The only workaround I can think of right now is to use put_change/3:

def changeset(account, attrs) do
  account
  |> put_change(:balance, Decimal.new("0.0"))
end

However, I prefer to do this on the migration itself. How do I do it?

Solution

  • I asked this same question on Elixir Slack and I was told that the first one should work.

    I checked again and the first one DOES work. It's just that Repo.insert() returns the column as nil, but it shows up as #Decimal<0E-10> if I retrieve the record again, which means the default value does work.