The present disclosure is related to devices, systems, and methods for transferring data using unique identifiers of relational databases. An example system can include a first server hosting a relational database and a second server coupled to the first server. The second server can be configured to assign a quantity of unique identifiers of a table of the relational database to each of a plurality of groups, perform a first transfer operation to transfer data corresponding to a first one of the plurality of groups via a first core of processing resources of the first server, and perform a second transfer operation to transfer data corresponding to a second one of the plurality of groups via a second core of the processing resources of the first server. The first transfer operation can be performed in parallel with the second transfer operation.