The discriminant tells us there are two roots when positive, one root when zero, and no roots when negative. b^2-4ac = (-8)^2-4*3*1 = 52 is positive, so there are two roots. The discriminant is just part of the quadratic equation. The quadratic equation gives us the exact real number roots of any equation in the form ax^2+bx+c=0. The quadratic equation is x = (-b \pm sqrt(b^2-4ac))/(2a), where \pm means that we have two values, one using + (addition) and one using - (subtraction). Let D = b^2-4ac.
RE: what is the difference between database and data w... Database is the place where the data is taken as a base and managed to get avialable fast and efficient access. Dataware house is the place where the application data is managed for analysis and reporting purposes.
SQL Data Warehouse uses a node based architecture. Applications connect and issue T-SQL commands to a Control node, which is the single point of entry for the data warehouse. The Control node runs the MPP engine which optimizes queries for parallel processing, and then passes operations to Compute nodes to do their work in parallel.