A system includes reception of a first instruction at a first system to effect a first change to a hierarchy data model, storage of a first record including first values specifying the first change in a local memory of the first system, reception of a second instruction to effect a second change to the hierarchy data model, storage of a second record including second values specifying the second change in the local memory of the first computer system, reception of an instruction to save the changed hierarchy data model, and, in response to the instruction, transmit the first record and the second record to a second system. The first record and the second record are received and merged to generate a third record including third values specifying a third change to the hierarchy data model, and a query language statement is generated to effect the third change to the hierarchy data model based on the third record.