Systems and methods are provided for changing a data structure, which an application program in a computer system uses to access database systems. According to an exemplary method, an application program communicates with a first database system to store entries in a source table having a first data structure. The method further includes creating a destination table in the first database system, such that the destination table has a second data structure and recording the type of change for those entries in the source table, which are changed when the application program communicates with the source table. The method further includes copying the destination table into a second database system and copying the source table in the second database system. Moreover, the method may include converting the entries in the copy of the source table from the first data structure to the second data structure and adjusting the changed entries in the source table to the copy of the source table, wherein the changed entries are copied from the source table as changed entries to the copy of the source table.