Short description:

Reverse engineering of the data model for the in-house development of asset and financial accounting through the analysis and documentation of COBOL record structures and the use of the data in the COBOL programs. The associated data basis is stored in an ISAM file system. The information serves as an input dataset for an interface between asset and financial accounting and IDEA inspection software.


Of particular importance for determining the relationships between the files are the file accesses in the COBOL programs of the asset and financial accounting, which was developed as an individual software. In other words, with what fields are the files accessed. The type of access is of no importance. Information on the technical and functional key fields can also be derived from the COBOL record structures and the file definitions of the ISAM file system. The data model is presented with MS Access after formatting of the COBOL record descriptions with the aid of various Office tools. Export of the data model to a text file is another step, which serves as an interface from the asset and financial accounting to the IDEA inspection software as a control component (see the data medium provision as per GDPdU project).

Technical description:

In the framework of the digital data media provision for the tax inspection with the IDEA testing software, apart from the tax-relevant data stored in tables, the relationship of the individual data records to each other is also required. The storage of data in indexed sequential file systems does not permit the presentation of the foreign key relationships between files. In old systems, these are often stored in the program code or inadequately documented. The field descriptions of the data records mostly exist as included structures written in the relevant programming language, or have to be derived directly from the program code. A reverse engineering of the data model, especially the foreign key relationships, is therefore only possible by analyzing the programs and data record descriptions, while incorporating specialist knowledge from the area of asset and financial accounting.