Federated queries
Federated queries allow you to retrieve information from various data sources without the need to transfer data from those sources into YDB. Using YQL queries, you can access external databases without duplicating data between systems.
To work with data stored in external DBMSs, simply create an external data source. To work with unschematized data stored in S3 buckets, you additionally need to create an external table. In both cases, you must first create secrets that store confidential data required for authentication in external systems.
You can learn about the internal structure of the federated query processing system in the section on architecture. Detailed information on working with various data sources is provided in the respective sections: