MariaDB function is a stored program that is used to pass parameters into them and return a value
We can easily create and drop functions in MariaDB.
# Create Function (MariaDB):
You can create your own function in MariaDB:
Syntax:
CREATE
[ DEFINER = { CURRENT_USER | user_name } ]
FUNCTION function_name [ (parameter datatype [, parameter datatype]) ]
RETURNS return_datatype [ LANGUAGE SQL
| DETERMINISTIC
| NOT DETERMINISTIC
| { CONTAINS SQL
| NO SQL
| READS SQL DATA
| MODIFIES SQL DATA }
| SQL SECURITY { DEFINER | INVOKER }
| COMMENT 'comment_value'
BEGIN
declaration_section
executable_section
END;
Example
Create a function CalcValue in MariaDB database.
DELIMITER //
CREATE FUNCTION CalcValue ( starting_value INT )
RETURNS INT DETERMINISTIC
BEGIN
DECLARE total_value INT;
SET total_value = 0;
label1: WHILE total_value <= 3000 DO
SET total_value = total_value + starting_value;
END WHILE label1;
RETURN total_value;
END; //
DELIMITER ;
DEFINER clause: it is an optional clause. If not specified, the definer is the user that created the function. If you wish to specify a different definer, you must include the DEFINER clause where user_name is the definer for the function.
function_name: It specifies the name to assign to this function in MariaDB.
return_datatype: It specifies the data type of the function's return value.
LANGUAGE SQL: It is in the syntax for portability but will have no impact on the function.
DETERMINISTIC: It means that the function will always return one result given a set of input parameters.
NOT DETERMINISTIC: It means that the function may return a different result given a set of input parameters. The result may be affected by table data, random numbers or server variables.
CONTAINS SQL: It is the default. It is an informative clause that tells MariaDB that the function contains SQL, but the database does not verify that this is true.
No SQL: An informative clause that is not used and will have no impact on the function.
READS SQL DATA: An informative clause that tells MariaDB that the function will read data using SELECT statements but does not modify any data.
MODIFIES SQL DATA: An informative clause that tells MariaDB that the function will modify SQL data using INSERT, UPDATE, DELETE, or other DDL statements.
declaration_section: The place in the function where you declare local variables.
executable_section: The place in the function where you enter the code for the function.
Output:
MariaDB Functions 2
MariaDB DROP Function
You can drop your created function very easily from your database.
Syntax:
DROP FUNCTION [ IF EXISTS ] function_name;
Parameter Explanation
function_name: It specifies the name of the function that you want to drop.
Example
We have created a function name "CalcValue". Now drop the function.
DROP FUNCTION CalcValue;
Now you can see that function is deleted and not present in the list anymore.
MariaDB Functions 5
