274

Data Integration Guidelines

Table 6.1

Comparing Different Integration Approaches (

continued

)

Operation

Connector 

EJB/JMS Approach

Web Services 

Approach

Approach

Security 

Can directly inte 

Provides application 

Limited. HTTPS is sup 

features

grate with the EISs 

server security mecha 

ported.

security model.

nisms.

6.4

Data Integration Guidelines

Recall that enterprise data may be kept in various types of data stores, including

relational databases, non relational databases, directory servers, and so forth. Some

common strategies that help to integrate data from these different types of data

stores are data mapping, data transformation, and data filtering. 

6.4.1 Data Mapping in EAI Applications

Enterprises use various types of data stores to hold data, and each such data store

persists the data according to its own layout and using its own data types. This is

true even within a single enterprise. Thus, there are many varied external representa 

tions of data. Often, external data representations are relational in nature because

most commonly data is stored in a relational database. EAI applications need to

know how to access this data. It is important to map external data to the data struc 

tures used within an EAI application.

An important issue to consider when integrating data sources is to decide on a

mapping layer. Generally, you have these options for relational data:

E

Create a formal object oriented data model. 

E

Create a generic data holder layer.

The formal object oriented data model relies on object relational mapping

technologies to map data from relational data sources to an object oriented

format. You may use such mapping technologies as Enterprise JavaBeans con 

tainer managed persistence, Java Data Objects, or even the data access object

strategy. There are a number of advantages to this option. For one, you can reap

the traditional advantages of an object oriented approach, notably reusability,

since you establish a mapping layer that can be reused by other applications.