Interview Questions and Answers

Indexes are used to improve database performance. Clustered indexes determine the physical order of data, while non-clustered indexes do not.

• Indexes are used to speed up data retrieval operations in a database.

• Clustered indexes determine the physical order of data in a table, while non-clustered indexes do not.

• A table can have only one clustered index, but multiple non-clustered indexes.

• Clustered indexes are generally faster for retrieving large ranges of data, while non-clus...read more

Singleton pattern restricts the instantiation of a class to a single instance and provides a global point of access to it.

• Create a private constructor to restrict instantiation of the class

• Create a private static instance of the class

• Create a public static method to access the instance

• Ensure thread safety if necessary

• Examples: Database connection, Logger, Configuration settings

Handle exceptions in stored procedures by using TRY-CATCH blocks.

• Use TRY-CATCH blocks to catch and handle exceptions

• Log the error message and severity level

• Rollback the transaction if necessary

• Rethrow the error if it cannot be handled

• Use RAISERROR to raise custom error messages

Query to delete duplicate rows from a table

• Use GROUP BY clause to group the rows by their unique values

• Use HAVING clause to filter out the groups with count greater than 1

• Use DELETE statement to delete the duplicate rows

throw is used to throw an exception while throw exception is used to throw a specific exception.

• throw is used to throw any type of exception while throw exception is used to throw a specific type of exception.

• throw exception is followed by the type of exception that needs to be thrown.

• throw can be used to throw any object while throw exception can only be used to throw an exception object.

• Example: throw new Exception("Something went wrong");

• Example: throw ex;