Flexible DDI storage

The current usage of DDI is heterogeneous. It varies over different versions of DDI, different grouping, and unequal interpretation of elements. Therefore, provider of services based on DDI implement complex database models for each developed application, resulting in high costs and application specific and non-reusable models. This paper shows a way to model the binding of DDI to applications in a way that it works independent of most version changes and interpretative differences in a standard like DDI without continuous reimplementation. Based on our DDI-FlatDB approach, shown first at EDDI 2015 & 2016, we present a complete implementation along the use case of a web-based questionnaire editor including sustainable solution for version management and efficient handling of large DDI structures. The user interface is adaptable to different usage scenarios to come. The application supports DDI-Lifecycle from the first question draft and hands over structured (meta-) data to survey institutes and data archives and supports the collaborative questionnaire development for the Pre-election Cross-Section of the German Longitudinal Election Study from early 2017 on.