Architecture for Integration and Migration of Information Systems by Using SOA Services across Heterogeneous System Boundaries

Abstract

The objective of this chapter is to describe how it is possible to integrate and/or migrate information system where local heterogeneous databases are involved. ERP (Enterprise Resource Planning) systems are very complex standardized information systems, and they are often vital for the companies that use them. Therefore, the authors use integration and migration of ERP systems as an example. Normally, ERP systems are migrated/converted overnight as it normally is not possible to integrate different ERP modules from different ERP suppliers. This is very risky as many types of industries cannot function without a running ERP system. The main focus of this chapter is to illustrate how it is possible to migrate/convert an ERP system module by module and thus minimizing the risk of staying without a functioning ERP system. In central databases, the consistency of data is normally implemented by using the ACID (Atomicity, Consistency, Isolation and Durability) properties of a DBMS (Data Base Management System). This is not possible if heterogeneous databases are involved and the availability of data also has to be optimized. Therefore, in this chapter, the authors use so called relaxed ACID properties across different database systems or ERP modules. The objective of designing relaxed ACID properties across different database systems is that the users can trust the data they use even if the involved database temporarily are inconsistent.