Reading data via bindings

Data bindings allow you to regularly query Yandex Data Streams data without having to specify connection settings and data format in each query.

Example of reading data using bindings:

SELECT
    JSON_VALUE(CAST(Data AS Json), "$.action") AS action
FROM bindings.`input_stream`
LIMIT 10;

Setting up a data bindingSetting up a data binding

To create a binding to read data from Yandex Data Streams:

1. Set up a data connection.

2. Navigate to Yandex Query.

3. In the left-hand panel, switch to the Bindings tab.

4. Click Create.

5. Under Connection parameters:

   1. In the Type field, select Data Streams.
   2. In the Connection field, select the connection you created in the first step.

6. Under Binding parameters:

   1. In the Name field, specify the binding name.
   2. In the Stream field, enter the name of the data stream in Yandex Data Streams.
   3. In the Compression field, specify the data compression method.
   4. In the Format field, specify the data format.
   5. In the Columns fields, specify the list of columns and their data types.

7. To validate the data, click Preview.

8. Click Create.

Data modelData model

Data is transmitted via Yandex Data Streams in binary format. To read data using a binding, use an SQL statement of the following format:

SELECT
    <expression>
FROM bindings.`<binding_name>`
WHERE
    <filter>;

Where:

• <statement>: Statement that determines the result of the query.
• <binding_name>: Name of the data binding you created earlier.
• <filter>: Data filtering condition.

Data reading exampleData reading example

Query example for reading data from Yandex Data Streams via bindings:

$data =
SELECT
    JSON_VALUE(Data, "$.host") AS host,
    JSON_VALUE(Data, "$.count") AS count,
    JSON_VALUE(Data, "$.tag") AS tag,
FROM
(
    SELECT
        CAST(Data AS Json) AS Data
    FROM bindings.`binding_name`
)
WHERE
    JSON_VALUE(Data, "$.tag") = "my_tag";

SELECT
    *
FROM
    $data
LIMIT 10;

Where: