There are some obvious advantages in integrating information from multiple data sources. Such integration alleviates the burden of duplicating data gathering efforts, and enables the extraction of information that would otherwise be impossible(Subrahmanian, et al., 1996).

Subrahmanian, et al. (1996) gives the following examples of benefits of data integration:

• "... law enforcement agencies such as Interpol benefit from the ability to access databases of various national police forces, to assist their effort in fighting international terrorism, drug trafficking, and other criminal activities. Insurance companies, using data from external sources, including other insurance company and police records, can identify possible fraudulent claims. Medical researchers and epidemiologists, with access to records across geographical and ethnic boundaries, are in a better position to predict the progression of certain diseases. In each case, the information extracted from the integrated sources is not possible when the data sources are viewed in isolation."