Such architecture makes possible for all or almost all of the company employees to use an ERP system in their work. Apart from helpful record level security, replication, and encryption tools, this architecture is also attractive because a client license for Notes is priced much lower than the one for SAP/R3.

Furthermore, it's also possible to preliminarily process the data passing through Notes, for example, to screen and approve various employee activity reports by their respective subdivision managers.

The second architecture implicates a looser relationship of systems. It uses Notes and Domino as a knowledge base and a system of preliminary assessment of the proposals, which are not ready for being processed by the standard SAP/R3 business processes. As a proposal stored in the "knowledge base" reaches a certain required level of readiness, it initiates the business process in the ERP system.

Integration technologies
From a technological point of view, these architectures could be divided according to the following. In the first approach, ERP system and Notes work with the same data, but in different phases of the data lifecycle. In the second architecture different data are used in Notes and the ERP system. Obviously, a real application can have a hybrid architecture, where some modules are closer to the first architecture, while the other modules have the second architecture type.

For the interaction within the second model, SAP provides a specific module LSX (Lotus Software Extension), a plug-in standard for LotusScript. By using that module, the Notes application can check the state of SAP/R3 objects and initiate some operations in R3. However, this technology is inconvenient for a mass data exchange between systems, which is critical for the first approach.

The best results within the first approach are achieved using LEI (Lotus Enterprise Integrator), a separately delivered Domino server module, which provides high-speed data exchange between Notes and Domino and other relational and non-relational DBMSs. Data exchange could be accompanied by data transformation and filtering. LEI contains a dedicated connector to exchange data with SAP/R3.

To sum up, in this article we have considered only relatively simple scenarios of two-sided integration of ERP systems with Notes. More complicated scenarios, which involve the other data sources (for example, transaction servers and application servers, such as IBM WebSphere), will be reviewed in a separate article later.

Dmitry Irtegov has four years experience in Lotus Notes and Domino software development, business support system development, and system integration working for Novosoft LLC (at http://www.novosoft.us) as team leader and system architect. He has taught at Novosibirsk State University, Physical and Informational Technology departments. Courses include Operating Systems, Unix System Calls & Libraries, and Multithreaded Programming. He is the author of Introduction to Operating Systems (in Russian).