Data warehousing is an integrated collection of data from multiple systems and is used as the basis for intelligent decision making. As a first step in Data warehousing it is important to identify the requirements including:
When we begin to initially develop the data warehouse we will begin with one functional area or subsystem and target one user group’s requirements. This is an iterative process and will be incremented by each user group or functional area and so on and so forth. This will be based on the organization’s requirements for information and the priority assigned. As we proceed with the data warehouse development we will learn from the prior data sets. As each iteration progresses, the speed of development increases and the results are quick.
The Data warehouse is populated through a series of steps:
In every organization it is important to understand the challenges and complexity that occurs in a data warehouse development. Sometimes the data warehouse may require new technology and hardware and software. The extract of datasets may be very difficult and arduous and the data may need to be corrected and reformatted for the new system. If data sources are from multiple environments it adds more complexity to the data warehouse project. In addition a team who understands the legacy environment and the data structures is required for a successful data warehouse project.
Perhaps the worst of all: Data relationships that have been built into old legacy program logic must be understood and unraveled before those files can be used as input.