Define an Ecto schema for Tablestore product use, there are some reasons make we do some wrapper base on Ecto.Schema:

• Since Tablestore product does not support(also not recommend) the first primary key(aka the partition key) autogenerated in server side, e.g. an auto increment sequence integer in server is not supported, so we set @primary_key as false by default when use EctoTablestore.Schema.
• Since Tablestore product's attribute column does not support DateTime or similar type in server side, so we use @timestamps_opts to pre-configure Ecto.Schema.timestamps/1 macro as an integer type for the generated inserted_at and updated_at fields.

If you have explicitly set @primary_key and @timestamps_opts(or Ecto.Schema.timestamps/1) in the defined schema, and then you can write use Ecto.Schema to make the schema definition more compatible in Ecto use, for example:

defmodule User do
  use Ecto.Schema

  @primary_key {:id, :id, autogenerate: false}

  schema "user" do
    field(:name, :string)
    timestamps(
      type: :integer,
      autogenerate: {System, :os_time, [:second]}
    )
  end
end

It equals to:

defmodule User do
  use EctoTablestore.Schema

  schema "user" do
    field(:id, :id, primary_key: true)
    field(:name, :string)
    timestamps()
  end
end

About primary key

• The primary key supports :id (integer()) and :binary_id (binary()).
• By default the :primary_key option is false.
• The first defined primary key by the written order in the schema is the partition key.
• Up to 4 primary key(s), it is limited by Tablestore product server side.
• Up to 1 primary key with autogenerate: true option, it is limited by Tablestore product server side.
• The primary key set with autogenerate: true will use the Tablestore product server's AUTO_INCREMENT feature.
• If the partition key set as autogenerate: true is not allowed to take advantage of the AUTO_INCREMENT feature which it is limited by server, but there is a built-in implement to use the Sequence to achieve the same atomic increment operation in ecto_tablestore library.

Here is an example about the primary keys:

defmodule User do
  use EctoTablestore.Schema

  schema "user" do
    field :outer_id, :binary_id, primary_key: true
    field :internal_id, :id, primary_key: true, autogenerate: true
    field :name, :string
    field :desc
  end
end

By default, if not explicitly set field type will process it as a :string type.