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Building Database Applications in Elixir with Ecto

Capture Errors

Understand how to use Ecto changesets to manage errors during database insertions and updates. Learn how to handle validation and constraint errors efficiently by leveraging the changeset workflow and reporting them for user feedback. This lesson helps you ensure data integrity and handle errors in one place for robust Elixir applications.

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The last step of the process is sending our changeset to Repo and seeing what happens. This section will see how changesets help us track errors and report them to the user.

Typical changeset workflow

When we look back at our example from the beginning of the chapter, we can see the entire changeset workflow, as follows.

Elixir
params = %{name: "Gene Harris"} 
changeset =
  %Artist{}\
  |> cast(params, [:name])\
  |> validate_required([:name])
case Repo.insert(changeset) do
  {:ok, artist} -> IO.puts("Record for #{artist.name} was created.") 
  {:error, changeset} -> IO.inspect(changeset.errors)
end

This is how we handle inserting a new record. If we were updating an existing record, we would pass the changeset into Repo.update. In either case, developers typically follow the pattern shown here: ...