DSS is the access and analytical representation of data stored in a Data Warehouse. Information must be retrieved quickly and represented in a readable format for users, the information must be correct and readily available. Companies are recognizing that the sooner they get their information, the quicker they can react to changing market needs - No longer can they wait for a monthly or weekly report. Transferring data from other systems such as IBM, DEC, and HP requires sophisticated data loading techniques. Speed is also an issue, when loading millions of records in a limited time window, inserting one record at a time into the database just doesn't cut the mustard.
Data needs to be copied in bulk transfer modes, in parallel threads, using buffered file access.
Once data exists in the Warehouse then the maintenance work begins, managing disk space, TMF dumps, validation, indexes, views, and report programs. The typical IS staff is lacking the information and experience to fully investigate and perform these tasks. Building a Data Warehouse requires a well thought-out plan, an understanding of the system architecture, a comprehensive database model, and access to tools and utilities that are not widely known. It is difficult to find a member of your IS staff that has performed even one Data Warehouse dataload. In large data loading, mistakes can be costly.