tag:harmeetdwh.blog.co.uk,2009-11-11:/MokoFeed2009-11-11T20:24:59+01:00tag:harmeetdwh.blog.co.uk,2008-08-19:/2008/08/19/datawarehouse-4608617/harmeet2008-08-19T13:29:19+02:002008-08-19T13:33:44+02:00 <p><strong><u>What is Datawarehouse?</u></strong></p> <p>According to W.H.Inmon...A Datawarehouse is nothing but a<br> <strong>Subject-Oriented<br> Time-Variant<br> Non-Volatile<br> Integreted</strong><br> storage of data.</p> <p><strong>Subject-Oriented:</strong> Subject-Oriented means it describes about a particular subject like Customer, Sales and Product.</p> <p><strong>Time-Variant:</strong> It means according to time data in datawarehouse changes beacause from time to time data will be loaded into the datawarehouse.</p> <p><strong>Non-Volatile:</strong> Once data is loaded into the datawarehouse it must not be deleted.</p> <p><strong>Integrated:</strong> i.e. data from different sources will be loaded and placed into one place(datawarehouse).</p> <p>According to Ralph Kimbal, a datawarehouse is a copy of transactional data used for analysis purpose.</p> <p><strong><u>Schemas:</u></strong> There are different types of schemas are there for designing datawarehouse. They are<br> <strong>STAR SCHEMA<br> SNOW-FLAKE SCHEMA</strong></p> <p> <small> <a href="http://harmeetdwh.blog.co.uk/2008/08/19/datawarehouse-4608617/#comments">Comments</a> </small> </p>