数据仓库介绍.ppt

Data Warehousing Introduction Basic Elements Basic Processes Evolution of Decision Support Systems1960’s Magnetic Tape Master Files Reports Evolution of Decision Support Systems1970’s DASD Direct Access Storage Devices DBMS Data Base Management Systems OLTP – On Line Transaction Processing A type of computer processing in which the computer responds immediately to user requests OLTP on Databases Database defined as a single source of data for all processing Evolution of Decision Support Systems1980’s PC/4GL Technology end-users able to directly control data and systems (notion that data can be used for more than OLTP) Management Information System MIS (later known as Decision Support Systems-DSS) defined as processing used to drive management decisions (as opposed to processing exclusively used to drive detailed operational decisions) single-database-serving-all-purpose paradigm One DBMS supporting both regular tr. processing and MIS/DDS Extract Processing Extract Program rummages through a file or database, uses some criteria for selection, and, upon finding qualified data, transports the data over onto another file or database used to move data used for DDS out of the way of high performance on line transaction processing and to give the DSS user the control over that data Evolution of Decision Support SystemsEarly 1990’s Proliferation of Extracts Extracts everywhere (and extracts of extracts, and extracts of extracts of extracts, and so forth) Productivity Problems In order to write a corporate report Data must be located Lots of customized programs must be written The programs must cross every technology that the company has Inability to go from Data to Information Due to the following: Data Applications were built to service the needs of current transaction processing They were never designed to hold the historical data needed for DSS analysis Evolution of Decision Support SystemsEarly 1990’s Lack of Credibility of Data E.g. Account activit