. What are different execute methods of ADO.NET command object?

ExecuteScalar method returns a single value from the first row and first column of the resultset obtained from the execution of SQL query.
ExecuteNonQuery method executes the DML SQL query such as insert, delete or update and returns the number of rows affected by this action.
ExecuteReader method returns DataReader object which is a forward-only resultset.
ExecuteXMLReader method is available for SQL Server 2000 or later. Upon execution it builds XMLReader object from standard SQL query.