MySQL のFederated Table としてAvro データを連携利用する

こんにちは！ドライバー周りのヘルプドキュメントを担当している古川です。

SQL Gateway を使って、MySQL リモーティングサービスを作成し、Avro のMySQL Federated Table を構築できます。CData ODBC Driver for Avro のMySQL インターフェースのdeamon になります。サービス起動後、MySQL のFEDERATED ストレージエンジンを使ってサーバーおよびテーブルを作成します。Avro データ をMySQL テーブルのように使いましょう。

Avro データへの接続

If you have not already done so, provide values for the required connection properties in the data source name (DSN). You can use the built-in Microsoft ODBC Data Source Administrator to configure the DSN. This is also the last step of the driver installation. See the "Getting Started" chapter in the help documentation for a guide to using the Microsoft ODBC Data Source Administrator to create and configure a DSN.

URI 接続プロパティをAvro ファイルの場所に設定して、ローカルのAvro ファイルに接続します。

SQL Gateway の設定

See the SQL Gateway Overview to set up connectivity to Avro データ as a virtual MySQL database. You will configure a MySQL remoting service that listens for MySQL requests from clients. The service can be configured in the SQL Gateway UI.

Avro データ のFEDERATED サーバーおよびテーブルを作成

After you have configured and started the service, create a FEDERATED server to simplify the process of creating FEDERATED tables:

FEDERATED サーバーの作成

The following statement will create a FEDERATED server based on the ODBC Driver for Avro. Note that the username and password of the FEDERATED server must match a user account you defined on the Users tab of the SQL Gateway.

CREATE SERVER fedAvro
FOREIGN DATA WRAPPER mysql
OPTIONS (USER 'sql_gateway_user', PASSWORD 'sql_gateway_passwd', HOST 'sql_gateway_host', PORT ####, DATABASE 'CData Avro Sys');

FEDERATED テーブルの作成

To create a FEDERATED table using our newly created server, use the CONNECTION keyword and pass the name of the FEDERATED server and the remote table (SampleTable_1). Refer to the following template for the statement to create a FEDERATED table:

CREATE TABLE fed_sampletable_1 (
  ...,
  id  TYPE(LEN),
  column1  TYPE(LEN),
  ...,
)
ENGINE=FEDERATED
DEFAULT CHARSET=latin1
CONNECTION='fedAvro/sampletable_1';

NOTE: The table schema for the FEDERATED table must match the remote table schema exactly. You can always connect directly to the MySQL remoting service using any MySQL client and run a SHOW CREATE TABLE query to get the table schema.

クエリの実行

You can now execute queries to the Avro FEDERATED tables from any tool that can connect to MySQL, which is particularly useful if you need to JOIN data from a local table with data from Avro. Refer to the following example:

SELECT 
  fed_sampletable_1.id, 
  local_table.custom_field 
FROM 
  local_table 
JOIN 
  fed_sampletable_1 
ON 
  local_table.foreign_id = fed_sampletable_1.id;