PolyBase で外部データソースとしてCosmos DB を連携利用





Cosmos DB ODBC Driver

使いやすいUnix 用Cosmos DB ODBC Driver。Unicode 対応32ビットおよび64ビットODBC。

CData ODBC Driver for Cosmos DB とSQL Server 2019 のPolyBase を使って、リアルタイムCosmos DB data に外部データソースとしてアクセス。

SQL Server のPolyBase は、データベーステーブルをクエリするTransact-SQL シンタックスを使って、外部データにクエリする仕組みです。 CData ODBC Drivers for Cosmos DB data を組み合わせて使うことで、SQL Server データと同じようにCosmos DB data へのアクセスが可能です。 本記事では、PolyBase 外部データソースへのCosmos DB data の設定から、T-SQL クエリを使ったCosmos DB data へのアクセスを行います。

The CData ODBC drivers offer unmatched performance for interacting with live Cosmos DB data using PolyBase due to optimized data processing built into the driver. When you issue complex SQL queries from SQL Server to Cosmos DB, the driver pushes down supported SQL operations, like filters and aggregations, directly to Cosmos DB and utilizes the embedded SQL engine to process unsupported operations (often SQL functions and JOIN operations) client-side. And with PolyBase, you can also join SQL Server data with Cosmos DB data, using a single query to pull data from distributed sources.

Cosmos DB への接続

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs. To create an external data source in SQL Server using PolyBase, configure a System DSN (CData Cosmos DB Sys is created automatically).

SQL API を使ってCosmos DB アカウントに接続するために必要な接続文字列を取得するには、Azure Portal にログインして[Azure Cosmos DB]を選択し、自分のアカウントを選択します。[Settings]セクションで、[Connection String]をクリックして次の値を設定します。

  • AccountEndpoint: 値は、Cosmos DB アカウントの[Keys]ブレードからのCosmos DB アカウントURL である必要があります。
  • AccountKey: Azure ポータルで、Cosmos DB サービスに移動してAzure Cosmos DB アカウントを選択します。リソースメニューから、 [Keys]ページに移動します。[PRIMARY KEY]値を見つけ、Token をこの値に設定します。

Click "Test Connection" to ensure that the DSN is connected to Cosmos DB properly. Navigate to the Tables tab to review the table definitions for Cosmos DB.

Cosmos DB Data の外部データソースの作成

After configuring the connection, you need to create a master encryption key and a credential database for the external data source.

Creating a Master Encryption Key

Execute the following SQL command to create a new master key, 'ENCRYPTION,' to encrypt the credentials for the external data source.


Creating a Credential Database

Execute the following SQL command to create credentials for the external data source connected to Cosmos DB data.

NOTE: Since Cosmos DB does not require a User or Password to authenticate, you may use whatever values you wish for IDENTITY and SECRET.

WITH IDENTITY = 'username', SECRET = 'password';

Create an External Data Source for Cosmos DB

Execute the following SQL command to create an external data source for Cosmos DB with PolyBase, using the DSN and credentials configured earlier.

For Cosmos DB, set SERVERNAME to 'localhost' or '' and leave PORT empty. PUSHDOWN is set to ON by default, meaning the ODBC Driver can leverage server-side processing for complex queries.

CREATE EXTERNAL DATA SOURCE cdata_cosmosdb_source
  CREDENTIAL = cosmosdb_creds

Cosmos DB のExternal Table を作成

After creating the external data source, use CREATE EXTERNAL TABLE statements to link to Cosmos DB data from your SQL Server instance. The table column definitions must match those exposed by the CData ODBC Driver for Cosmos DB. You can refer to the Tables tab of the DSN Configuration Wizard to see the table definition.

Sample CREATE TABLE Statement

The statement to create an external table based on a Cosmos DB Customers would look similar to the following:

  City [nvarchar](255) NULL,
  CompanyName [nvarchar](255) NULL,
) WITH ( 

Having created external tables for Cosmos DB in your SQL Server instance, you are now able to query local and remote data simultaneously. Thanks to built-in query processing in the CData ODBC Driver, you know that as much query processing as possible is being pushed to Cosmos DB, freeing up local resources and computing power. Download a free, 30-day trial of the ODBC Driver for Cosmos DB and start working with live Cosmos DB data alongside your SQL Server data today.