This association between a stream source and a Lambda function is called the event source mapping.
This event source mapping is relevant only in the AWS Lambda pull model, where AWS Lambda invokes the function. For more information, go to AWS Lambda: How it Works in the AWS Lambda Developer Guide.
You provide mapping information (for example, which stream to read from and which Lambda function to invoke) in the request body.
Each event source, such as an Amazon Kinesis or a DynamoDB stream, can be associated with multiple AWS Lambda function. A given Lambda function can be associated with multiple AWS event sources.
If you are using versioning, you can specify a specific function version or an alias via the function name parameter. For more information about versioning, see AWS Lambda Function Versioning and Aliases.
This operation requires permission for the lambda:CreateEventSourceMapping
action.