The software evolution is a challenge for engineers. In fact, the high complexity of the software makes it difficult to perform the change. This may cause serious damage in the infodation system. Within the infomation system cooperating by the way of federation, the effects are more critical. It appears necessary to provide tools that support the a priori chauge impact analysis. In this paper, we propose the Source Code Software Components Structural Model (SC²SM). This models applications manipulating persistent objects, stored in an ODMG-compliant database system. The SC²SM defines software components multigraphs, that represent local and federated database schemas, programs source codes and their relationships. The multigraph representation is the way to process the u priori change impact analysis, using a knowledge base system.