Procedures are sort of functions in a database. Procedures are created when you want to perform a task repetitively.

MariaDB procedure is a stored program that is used to pass parameters into it. It does not return a value as a function does.

You can create and drop procedures like functions.

# Create Procedure (MariaDB):

You can create your procedure just like you create a function in MariaDB.

Syntax:

Parameter Explanation

DEFINER clause: Optional.

procedure_name: The name to assign to this procedure in MariaDB.

Parameter: One or more parameters passed into the procedure. When creating a procedure, there are three types of parameters that can be declared:

IN: The parameter can be referenced by the procedure. The value of the parameter cannot be overwritten by the procedure.

OUT: The parameter cannot be referenced by the procedure, but the value of the parameter can be overwritten by the procedure.

IN OUT: The parameter can be referenced by the procedure, and the value of the parameter can be overwritten by the procedure.

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: It is an informative clause that is not used and will have no impact on the function.

READS SQL DATA: It is an informative clause that tells MariaDB that the function will read data using SELECT statements but does not modify any data.

MODIFIES SQL DATA: It is 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 procedure where you declare local variables.

executable_section: The place in the procedure where you enter the code for the procedure.

Example

Create a procedure named "CalcValue" in MariaDB database.

1. DELIMITER //    
2. CREATE procedure CalcValue ( OUT ending_value INT )    
3. DETERMINISTIC    
4. BEGIN    
5.    DECLARE total_value INT;    
6.    SET total_value = 50;    
7.    label1: WHILE total_value 
8.      SET total_value = total_value * 2;    
9.    END WHILE label1;    
10.    SET ending_value = total_value;    
11. END; //    
12. DELIMITER ;     

Procedure is created successfully:

You can refer your new procedure as follows

MariaDB DROP Procedure:

You can drop procedure by using the following command:

Syntax:

1. DROP procedure [ IF EXISTS ] procedure_name;     

Parameter Explanation:

procedure_name: It specifies the name of the procedure that you want to drop.

Example

1. DROP procedure CalcValue;  

You can see that the procedure is dropped now and it is not available in the list.