Scheduled tasks is the bassically use of the completing task which is schededule by any user who use the system administrator, let user automate processes that run on regular or predictable cycles. user can decide his task for the perticule schedule time such as cube prossessing, for running the during times of slow business activity. User can also determine the order in which tasks run by creating job steps within a SQL Server Agent job. E.g. back up database, Update Stats of Tables. Job steps give user control over flow of execution. If one job fails, user can configure SQL Server Agent to continue to run the remaining tasks or to stop execution.

A database key is a attribute utilized to sort and identify data in some manner. There are many keys: 1. Primary keys 2. Foreign Keys 3. Candidate keys 4. Alternate keys 5. Conposite key

A relation schema R is said to be in 5 NF 1.It is in 4NF 2.A Relation schema R is said to be 5NF if for every join dependency {R1, R2, ..., Rn} that holds R, one the following is true Ri = R for some i. and The join dependency is implied by the set of FD, over R in which the left side is key of R.

A relation schema R is said to be in 4NF 1.It is in BCNF 2.For every Multivalued dependency X --> Y that holds over R, Either X is subset or equal to (or) XY = R. or X is a super key

A relation schema R is in BCNF 1.It is in 3NF 2.Additional constraints that for every FD X -> A, X must be a candidate key

A relation schema R is in 3NF 1.It is in 2NF 2.No non-prime attribute A in R is transitively dependent on the primary key. Transitive dependent means if there a set of attribute Z that are neither a primary or candidate key and both X-->Z and Y-->Z holds.

A relation schema R is in 2NF when 1.It is in 1NF 2.Every non-prime attribute A in R is fully functionally dependent on primary key.