Enterprise Application Integration in business management:

Enterprises are facing the challenge of integrating complex software systems
in a heterogeneous information technology landscape that has grown in an
evolutionary way for years, if not for decades. Most of the application systems
have been developed independently of each other, and each application stores
its data locally, either in a database system or some other data store, leading
to siloed applications.
Data heterogeneity issues occur if a logical data item�for instance, a
customer address�is stored multiple times in different siloed applications.
Assume that customer data is stored in an enterprise resource planning system
and a customer relationship management system. Although both systems use
a relational database as storage facility, the data structures will be different
and not immediately comparable.
These differences involve both the types of particular data fields (strings
of different length for attribute CustomerName), but also the names of the
attributes. In the customer example, in one system the attribute CAddr will
denote the address of the customer, while in the other system the attribute
StreetAdrC denotes the address.
The next level of heterogeneity regards the semantics of the attributes.
Assume there is an attribute Price in the product tables of two application
systems. The naming of the attribute does not indicate whether the price
includes or excludes value-added tax. These semantic differences need to be
sorted out if the systems are integrated. Data integration technologies are
used to cope with these syntactic and semantic difficulties.
Data integration is an important aspect in enterprise application integration.
In this section, the traditional point-to-point enterprise application.