blockscout/apps/explorer/priv/repo/migrations/20180117221923_create_transactions.exs

defmodule Explorer.Repo.Migrations.CreateTransactions do
  use Ecto.Migration

  def change do
    create table(:transactions, primary_key: false) do
      add(:gas, :numeric, precision: 100, null: false)
      add(:gas_price, :numeric, precision: 100, null: false)
      add(:hash, :bytea, null: false, primary_key: true)

      # `null` when a pending transaction
      add(:index, :integer, null: true)

      add(:input, :text, null: false)
      add(:nonce, :integer, null: false)
      add(:public_key, :string, null: false)
      add(:r, :string, null: false)
      add(:s, :string, null: false)
      add(:standard_v, :string, null: false)
      add(:v, :string, null: false)
      add(:value, :numeric, precision: 100, null: false)

      timestamps(null: false)

      # `null` when a pending transaction
      add(:block_hash, references(:blocks, column: :hash, on_delete: :delete_all, type: :bytea), null: true)

      add(:from_address_hash, references(:addresses, column: :hash, on_delete: :delete_all, type: :bytea), null: false)
      # `null` when it is a contract creation transaction
      add(:to_address_hash, references(:addresses, column: :hash, on_delete: :delete_all, type: :bytea), null: true)
    end

    create(
      constraint(
        :transactions,
        :indexed,
        check: "(block_hash IS NULL AND index IS NULL) OR (block_hash IS NOT NULL AND index IS NOT NULL)"
      )
    )

    create(index(:transactions, :block_hash))
    create(index(:transactions, :from_address_hash))
    create(index(:transactions, :to_address_hash))

    create(index(:transactions, :inserted_at))
    create(index(:transactions, :updated_at))

    create(unique_index(:transactions, [:block_hash, :index]))
  end
end