1.Name the classes are found in System.Data.Common NameSpace?
Ans:
DataColumnMapping
2)DataTableMapping
2. Can a table have two primary keys?
Ans:-A table can have Only One Primary key. But a table can have
composite Primary key. that means we can create composite
primary key .
upto 16 columns only.
3. select highest salary without using "top" ?
Ans:SELECT MAX(Salary) ThirdHighest
FROM Employee t
WHERE Salary <
(SELECT MAX(Salary)
FROM Employee t
WHERE Salary <
(SELECT MAX(Salary)
FROM Employee t));
4. select highest salary using "top" ?
SELECT TOP 1 salary
FROM (
SELECT DISTINCT TOP n salary
FROM employee
ORDER BY salary DESC) a
ORDER BY salary
