Oracle Methods


Method is block of PL/SQL code used to encapsulate the data access method for an object, it is also specified as part of the abstract datatype specification as (CREATE OR REPLACE TYPE  MARKS_TY AS OBJECT) and their body declaration as (CREATE OR REPLACE TYPE BODY MARKS_TY AS MEMBER FUNCTION TOTMARKS()). Before to learn methods it is recommanded to get overview the abstract datatype teqniques. 

Creating specification

CREATE OR REPLACE TYPE MARKS_TY AS OBJECT (M1 NUMBER(3), M2 NUMBER(3), M3 NUMBER(3), MEMBER FUNCTION TOTMARKS(M1 IN NUMBER, M2 IN NUMBER, M3 IN NUMBER) RETURN NUMBER);

In above example, TOTMARKS is declaration of function which will be used later in function calling to get defined. 

Defining function (body declaration)

CREATE OR REPLACE TYPE BODY MARKS_TY AS MEMBER FUNCTION TOTMARKS(M1 NUMBER, M2 NUMBER, M3 NUMBER) RETURN NUMBER 
IS 
BEGIN
RETURN(M1+M2+M3);
END;
END;
/

Creating table using above abstract datatype MARKS_TY

CREATE TABLE STDMARKS
(STUDENT_ID NUMBER(4), MARKS MARKS_TY);

Inserting data into table

INSERT INTO STDMARKS VALUES
(1, MARKS_TY(85,84,73));

Selecting data from table

SELECT S.MARKS.TOTMARKS(S.MARKS.M1, S.MARKS.M2, S.MARKS.M3)
FROM STDMARKS S;

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