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Send queries using REST API

Overview​

Teradata Query Service is a REST API for Vantage that you can use to run standard SQL statements without managing client-side drivers. Use Query Service if you are looking to query and access the Analytics Database through a REST API.

This how-to provides examples of common use cases to help you get started with Query Service API.

Prerequisites​

Before starting, make sure you have:

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If you need a test instance of Vantage, you can provision one for free at https://clearscape.teradata.com

  • Query Service hostname and system name
  • Authorization credentials to connect to the database

Having trouble with the prerequisites? Contact Teradata for setup information.

Query Service API examples​

When using the examples, please keep in mind that:

  • The examples in this document use Python, and you can use these to create examples in your language of choice.
  • The examples provided here are complete and ready for you to use, although most require a little customization.
    • The examples in this document use the URL https://<QS_HOSTNAME>:1443/.
    • Replace the following variables with your own value:
      • <QS_HOSTNAME>: Server where Query Service is installed
      • <SYSTEM_NAME>: Preconfigured alias of the system
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If your Vantage instance is provided through ClearScape Analytics Experience,<QS_HOSTNAME>, is the host URL of your ClearScape Analytics Experience environment, <SYSTEM_NAME> is 'local'.

Connect to your Query Service instance​

Provide valid credentials to access the target Analytics Database using HTTP Basic or JWT authentication.

HTTP Basic authentication​

The database username and password are combined into a string ("username : password") which is then encoded using Base64. The API response contains the authorization method and encoded credentials.

Request

Response

JWT authentication​

Prerequisites:

  • The user must already exist in the database.
  • The database must be JWT enabled.

Request

Response

Make a simple API request with basic options​

In the following example, the request includes:

  • SELECT * FROM DBC.DBCInfo: The query to the system with the alias <SYSTEM_NAME>.

  • 'format': 'OBJECT': The format for response. The formats supported are: JSON object, JSON array, and CSV.

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    The JSON object format creates one JSON object per row where the column name is the field name, and the column value is the field value.

  • 'includeColumns': true: The request to include column metadata, such as column names and types, in the response.

  • 'rowLimit': 4: The number of rows to be returned from a query.

Request

Response

For response parameters, see Query Service Installation, Configuration, and Usage Guide.

Request a response in CSV format​

To return an API response in CSV format, set the *format* field in the request with the value *CSV*.

The CSV format contains only the query results and not response metadata. The response contains a line for each row, where each line contains the row columns separated by a comma. The following example returns the data as comma-separated values.

Request

Response

Use explicit session to submit a query​

Use explicit sessions when a transaction needs to span multiple requests or when using volatile tables. These sessions are only reused if you reference the sessions in a query request. The request is queued if a request references an explicit session already in use.

  1. Create a session Send a POST request to the /system/<SYSTEM_NAME>/sessions endpoint. The request creates a new database session and returns the session details as the response.

    In the following example, the request includes 'auto_commit': True - the request to commit the query upon completion.

    Request

    Response

  2. Use the session created in Step 1 to submit queries

    Send a POST request to the /system/<SYSTEM_NAME>/queries endpoint.

    The request submits queries to the target system and returns the release and version number of the target system.

    In the following example, the request includes:

    • SELECT * FROM DBC.DBCInfo: The query to the system with the alias <SYSTEM_NAME>.
    • 'format': 'OBJECT': The format for response.
    • 'Session' : <Session ID>: The session ID returned in Step 1 to create an explicit session.

    Request

    Response

Use asynchronous queries​

Use asynchronous queries when a system or network performance is affected by querying a large group of data or long running queries.

  1. Submit asynchronous queries to the target system and retrieve a Query ID Send a POST request to the /system/<SYSTEM_NAME>/queries endpoint. In the following example, the request includes:

    • SELECT * FROM DBC.DBCInfo: The query to the system with the alias <SYSTEM_NAME>.
    • 'format': 'OBJECT': The format for response.
    • 'spooled_result_set': True: The indication that the request is asynchronous.

    Request

    Response

  2. Get query details using the ID retrieved from Step 1

    Send a GET request to the /system/<SYSTEM_NAME>/queries/<queryID> endpoint, replacing <queryID> with the ID retrieved from Step 1.

    The request returns the details of the specific query, including queryState, queueOrder, queueDuration, and so on. For a complete list of the response fields and their descriptions, see Query Service Installation, Configuration, and Usage Guide.

    Request

    Response

  3. View resultset for asynchronous query

    Send a GET request to the /system/<SYSTEM_NAME>/queries/<queryID>/results endpoint, replacing <queryID> with the ID retrieved from Step 1.

    The request returns an array of the result sets and update counts produced by the submitted query.

    Request

    Response

Get a list of active or queued queries​

Send a GET request to the /system/<SYSTEM_NAME>/queries endpoint. The request returns the IDs of active queries.

Request

Response

Resources​

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If you have any questions or need further assistance, please visit our community forum where you can get support and interact with other community members.

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