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We must have SUPER privileges to create or destroy triggers with the help of a CREATE or DROP statement. Other than that if the triggered statements use OLD or NEW then there are some additional privileges as follows which we require −To assign the value of a column with SET NEW.column_name = value then we must have the UPDATE privilege for the column.To use NEW.column_name in an expression to refer to the new value of a column, we must have the SELECT privilege for the column.
To loop through all the values of enum, use the Enum.GetValues().Firstly, set an Enum −public enum Grade { A, B, C, D, E, F };Now, with foreach loop, you need to loop through Enum.GetValues(typeof(Grade)) −foreach (Grade g in Enum.GetValues(typeof(Grade))) { Console.WriteLine(g); }Here is the complete code −Example Live Demousing System; public class EnumExample { public enum Grade { A, B, C, D, E, F }; public static void Main() { foreach (Grade g in Enum.GetValues(typeof(Grade))) { Console.WriteLine(g); } } }OutputA B C D E F
While querying data from a MySQL table, we may get duplicate values from a column. With the help of the DISTINCT clause in the SELECT statement, we can get rid of duplicate data in the result set.SyntaxSELECT DISTINCT Columns FROM Table_name WHERE conditions;ExampleFor example, we have a table named ‘tender’ having the following columns −mysql> Select * from tender; +----------+--------------+--------------+-------+ | clientid | client_Fname | Client_Lname | value | +----------+--------------+--------------+-------+ | 100 | Mohan | Kumar | 60000 | | 101 | Sohan | Singh ... Read More
Check for the following conditions −For odd and even, check for the remainder when the number is divided by 2 −// checking for odd/ even if(n % 2 == 0) { Console.WriteLine("Even"); } else { Console.WriteLine("Odd"); }For positive, negative and checking whether a number is 0 or not −if (n < 0) { Console.WriteLine("Negative Number!"); } else if(n == 0) { Console.WriteLine("Zero"); } else { Console.WriteLine("Positive Number!"); }The following is the complete code:Example Live Demousing System; using System.Collections.Generic; public class Demo { public static void Main(string[] args) { int n = 19; ... Read More
We can destroy a trigger in two ways −Dropping a trigger explicitlyWith the help of the DROP statement, we can destroy a trigger explicitly. It can be understood with the help of the following example −mysql> DROP Trigger before_inser_studentage1; Query OK, 0 rows affected (0.05 sec)Dropping a trigger implicitlyA trigger will be destroyed implicitly if the table with which it is associated is destroyed or if the database which it is associated is destroyed.
Operating Systems have become quite complex and multifaceted with the advancement of time. However, that also means it is getting more and more difficult to design operating systems that satisfy all the specifications required these days. There are no complete solutions possible for design problems, but some approaches are more successful than others.Design Requirements in Operating SystemThe design requirements are quite hard to specify in an operating system. They are basically divided into two parts: User design requirements and System design requirements. Details about these are given as follows −User Design RequirementsThe operating system should be convenient, easy to use, ... Read More
It can be done with the help of the following statement −mysql> select * from information_schema.triggers where -> information_schema.triggers.trigger_schema like '%query%'\G *************************** 1. row *************************** TRIGGER_CATALOG: def TRIGGER_SCHEMA: query TRIGGER_NAME: trigger_before_delete_sample EVENT_MANIPULATION: DELETE EVENT_OBJECT_CATALOG: def EVENT_OBJECT_SCHEMA: query EVENT_OBJECT_TABLE: sample ACTION_ORDER: 1 ACTION_CONDITION: NULL ACTION_STATEMENT: BEGIN SET @count ... Read More
We can use the DISTINCT clause on more than columns in MySQL. In this case, the uniqueness of rows in the result set would depend on the combination of all columns.ExampleConsider the following table ‘testing’ having 10 rows −mysql> select * from testing; +------+---------+---------+ | id | fname | Lname | +------+---------+---------+ | 200 | Raman | Kumar | | 201 | Sahil | Bhalla | | 202 | Gaurav | NULL | | 203 | Aarav | NULL | | 204 | Harshit | Khurana | | 205 | Rahul ... Read More
A microkernel is the minimum software that is required to correctly implement an operating system. This includes memory, process scheduling mechanisms and basic inter-process communication.A diagram that demonstrates the architecture of a microkernel is as follows −In the above diagram, the microkernel contains basic requirements such as memory, process scheduling mechanisms and basic interprocess communication. The only software executing at the privileged level i.e. kernel mode is the microkernel. The other functions of the operating system are removed from the kernel mode and run in the user mode. These functions may be device drivers, file servers, application interprocess communication etc.The ... Read More
When we use the GROUP BY clause in the SELECT statement without using aggregate functions then it would behave like the DISTINCT clause. For example, we have the following table −mysql> Select * from testing; +------+---------+---------+ | id | fname | Lname | +------+---------+---------+ | 200 | Raman | Kumar | | 201 | Sahil | Bhalla | | 202 | Gaurav | NULL | | 203 | Aarav | NULL | | 204 | Harshit | Khurana | | 205 | Rahul | NULL | | 206 | ... Read More