This topic provides the DDL syntax that is used to create a Datagen source table, describes the parameters in the WITH clause, and provides sample code.

What is a Datagen source table?

A Datagen source table is a built-in connector of the Flink system. This connector periodically generates random data of the type that corresponds to the Datagen source table. If an error is returned when you create a source table of another type, but you cannot determine whether it is caused by a system error or an invalid setting of a parameter in the WITH clause of the source table, you can change the value of connector to datagen and click Run. If no error is returned, Realtime Compute for Apache Flink is normal. You must check the settings of parameters in the WITH clause.

Limits

Only Realtime Compute for Apache Flink that uses Ververica Runtime (VVR) 2.0.0 or later supports the Datagen connector.

DDL syntax

CREATE TABLE datagen_source (
  name VARCHAR,
  score BIGINT
) WITH (
  'connector' = 'datagen'
);

Parameters in the WITH clause

Parameter Description Required Remarks
connector The type of the source table. Yes Set the value to datagen.
rows-per-second The rate at which random data is generated. No Default value: 10000. Unit: records per second.
fields.#.length The length of the generated random string. No Default value: 100. The CHAR, VARCHAR, and STRING data types are supported.
fields.#.kind
  • For unbounded data in the data source, fields.#.kind specifies a random number generator. This is the default value.
  • For bounded data in the data source, fields.#.kind specifies a sequence generator.
No N/A.
fields.#.max The maximum value of the random number generator. No Only numeric values are supported.
fields.#.min The minimum value of the random number generator. No Only numeric values are supported.
fields.#.start The start value of the sequence generator. No N/A.
fields.#.end The end value of the sequence generator. No N/A.

Sample code

CREATE TEMPORARY table datagen_source(
  name VARCHAR
) WITH (
  'connector' = 'datagen'
);

CREATE TEMPORARY table datahub_sink(
  name  VARCHAR  
) WITH (
  'connector'='datahub',
  'endpoint'='<yourEndpoint>',
  'project'='<yourProject>',
  'topic'='<yourTopic>',
  'accessId'='<yourAccessId>',
  'accessKey'='<yourAccessKey>'
);

INSERT INTO datahub_sink
SELECT 
  LOWER(name)
from datagen_source;