Purpose of the EBAS diffxml file format

Differential extracts

EBAS extracts can be performed in a differential way (see EBAS Commandline User’s Guide, ebas_extract: Differential extracts), which means, only changes between a certain timestamp (diff state) and the current database state are extracted from the database. This way, a data user can synchronize a local data repository without downloading the full dataset each time. Data that have been added to EBAS since the diff state can be just extracted in their latest version and packed into normal data files. But information about data that have been changed or deleted can not be transferred in the normal data files. This information (which of the “old” data need to be thrown away) is need by the data recipient to make a differential extract useful. This is where the diffxml file comes in.