What is the Decision Support Systems in detail?

What is the Decision Support Systems in detail?
Basically it is an Management of Information System. Here decision takers are contacted to find out what are the type of decisions usually taken by them. The system is successful as much the variety of decision taken is revealed. Then information required for the decision is derived on the basis of the practice followed the decision maker, his logic, he rules and reliance on the information. After Having the data requirements finalised, logics of decision finalised, suitable database system is installed and application programs are developed to provide the decision maker the information, and options availabe from the database for various decisions he takes on his desktop. Data warehousing is a well known decision support system. it is also stated as a move from intuitive decision to informed decision.