Use self reference : Self « Object Oriented Database « Oracle PL / SQL

1. Oracle PL / SQL
2. Object Oriented Database
3. Self

Use self reference

SQL> CREATE OR REPLACE TYPE aobj AS object (
  2                    state CHAR(2),
  3                    amt NUMBER(5),
  4
  5                    MEMBER FUNCTION mult (times in number) RETURN number,
  6                    PRAGMA RESTRICT_REFERENCES(mult, WNDS));
  7  /

Type created.

SQL>
SQL>
SQL> -- 'self'
SQL>
SQL> CREATE OR REPLACE TYPE BODY aobj AS
  2  MEMBER FUNCTION mult (times in number) RETURN NUMBER
  3  IS
  4    BEGIN
  5      RETURN times * self.amt;
  6    END;
  7  END;
  8  /

Type body created.

SQL>
SQL>
SQL> CREATE TABLE aobjtable (arow aobj);

Table created.

SQL>
SQL>
SQL>
SQL> INSERT INTO aobjtable VALUES (aobj('FL',25));

1 row created.

SQL> INSERT INTO aobjtable VALUES (aobj('AL',35));

1 row created.

SQL> INSERT INTO aobjtable VALUES (aobj('OH',15));

1 row created.

SQL>
SQL> -- Use the function we created: use the table alias in our SELECT as well as the qualifier, arow:
SQL>
SQL> SELECT x.arow.state, x.arow.amt, x.arow.mult(2)
  2  FROM aobjtable x;

AR   AROW.AMT X.AROW.MULT(2)
-- ---------- --------------
FL         25             50
AL         35             70
OH         15             30

SQL>
SQL>
SQL> DESC aobjtable;
 Name                                                                                                  Null?    Type
 ----------------------------------------------------------------------------------------------------- -------- --------------------------------------------------------------------
 AROW                                                                                                   AOBJ

SQL>
SQL> drop table aobjtable;

Table dropped.

SQL>
SQL>
           
       

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