Defines a schema for Tablestore.

Since the atomic increment may need to return the increased value, EctoTablestore.Schema module underlying uses Ecto.Schema, and automatically append all :integer field type with read_after_writes: true option by default.

An Ecto schema is used to map any data source into an Elixir struct. The definition of the schema is possible through the API: tablestore_schema/2.

tablestore_schema/2 is typically used to map data from a persisted source, usually a Tablestore table, into Elixir structs and vice-versa. For this reason, the first argument of tablestore_schema/2 is the source(table) name. Structs defined with tablestore_schema/2 also contain a __meta__ field with metadata holding the status of struct, for example, if it has bee built, loaded or deleted.

Since Tablestore is a NoSQL database service, embedded_schema/1 is not supported so far.

About timestamps

Since Tablestore's column does not support DateTime type, use UTC timestamp (:integer type) as timestamps() macro for the generated inserted_at and updated_at fields by default.

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 tablestore_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.

Example

defmodule User do
  use EctoTablestore.Schema

  tablestore_schema "users" 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 :string type.