# Alibaba Tablestore adapter for Ecto

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Ecto 3.x adapter for Alibaba Tablestore, this is built on top of [`ex_aliyun_ots`]( to implement `Ecto.Adapter` and `Ecto.Adapter.Schema` behaviours.

Supported features:

* Compatible `Ecto.Repo` API.
* Support schema's `timestamps()` macro, make `inserted_at` and `updated_at` as an integer UTC timestamps.
* Support `:map` | `{:map, _}` | `:array` | `{:array, _}` field type, use Jason to encode the field value into :string when save, use Jason to simply decode the field value into `:map` | `:array` when read, the :keys option of Jason's decode always use :string.
* Support the partition key is autoincrementing, use the sequence feature provided by `ex_aliyun_ots`.
* Automatically converts the returned original row results into corresponding schema(s).
* Automatically generate the provided attribute-column field(s) of schema entity into the `filter` expression option of `GetRow` (see ``) and `BatchGet` (see `c:EctoTablestore.Repo.batch_get/1`) use `entity_full_match: true`, by default this option is `false`.
* Automatically generate the provided attribute-column field(s) of schema entity into the `condition` expression option of `BatchWrite`.
* Automatically map changeset's attribute-column field(s) into `UpdateRow` operation when call `c:EctoTablestore.Repo.update/2`:
  * Use atomic increment via `{:increment, integer()}` in changeset, and return the increased value in the corrsponding field(s) by default;
  * Set any attribute(s) of schema changeset as `nil` will `:delete_all` that attribute-column field(s);
  * Set existed attribute(s) in schema changeset will `:put` to save.

Implement Tablestore row related functions in `EctoTablestore.Repo` module, please see [document]( for details:

* PutRow
* GetRow
* UpdateRow
* DeleteRow
* GetRange
* StreamRange
* BatchGetRow
* BatchWriteRow
* Search

## Migration

Provide a simple migration to create table, please see `EctoTablestore.Migration` for details.

## Usage

1, Configure `My` instance(s) information of Alibaba Tablestore product.

use Mix.Config

# config for `ex_aliyun_ots`

config :ex_aliyun_ots, MyInstance,
  access_key_id: "MY_OTS_ACCESS_KEY",
  access_key_secret: "MY_OTS_ACCESS_KEY_SECRET"

config :ex_aliyun_ots,
  instances: [MyInstance]
# config for `ecto_tablestore`

config :my_otp_app, EctoTablestore.MyRepo,
  instance: MyInstance


2, Create the `EctoTablestore.MyRepo` module mentioned earlier in the configuration, use `EctoTablestore.Repo` and set required `otp_app` option with your OTP application's name.

defmodule EctoTablestore.MyRepo do
  use EctoTablestore.Repo,
    otp_app: :my_otp_app

3, Each repository in Ecto defines a `start_link/0` function that needs to be invoked before using the repository. In general, this function is not called directly, but used as
part of your application supervision tree.

Add `EctoTablestore.MyRepo` into your application start callback that defines and start your supervisor. You just need to edit `start/2` function to start the repo as a
supervisor on your application's supervisor:

def start(_type, _args) do
  children = [
    {EctoTablestore.MyRepo, []}

  opts = [strategy: :one_for_one, name: MyApp.Supervisor]
  Supervisor.start_link(children, opts)

4, After finish the above preparation, we can use `MyRepo` to operate data store.

## Integrate Hashids

Base on unique integer of atomic-increment sequence, provides a way to simply integrate `Hashids` to generate your *hash* ids when insert row(s), for `Repo.insert/2` or `Repo.batch_write/1`.

### use in schema

defmodule Module do
  use EctoTablestore.Schema

  tablestore_schema "table_name" do
    field(:id, :hashids, primary_key: true, autogenerate: true,
      hashids: [salt: "123", min_len: 2, alphabet: "..."])
    field(:content, :string)


  * The `primary_key` as true is required;
  * The `autogenerate` as true is required; 
  * The `salt`, `min_len`, and `alphabet` of hashids option is used for configuration options from ``.

### use in migration

Use `:hashids` as a type in `add` operation to define the partition key,
the principle behind this will use `ecto_tablestore_default_seq` as a global default table to maintain the sequences of all tables, if `ecto_tablestore_default_seq` is not existed, there will create this, if it is existed, please ignore the "OTSObjectAlreadyExist" error of requested table already exists.

defmodule EctoTablestore.TestRepo.Migrations.TestHashids do
  use EctoTablestore.Migration

  def change do
    create table("table_name") do
      add :id, :hashids, partition_key: true, auto_increment: true
      add :oid, :integer



  * The `partition_key` as true is required;
  * The `auto_increment` as true is required.

## References

Alibaba Tablestore product official references:

* [English document](
* [中文文档](

## License