в 13:45, 26 мая 2010

2010-05-26T13:45:19Z

Admin: 1 версия

2010-05-26T10:02:43Z

1 версия

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==Use self reference==



<source lang="sql">

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>

</source>

==Use self to reference member variable==



<source lang="sql">

SQL>
SQL>
SQL> create or replace
2 type employee as object(
3 name varchar2(100),
4 empno number,
5 hiredate date,
6 vacation_used number,
7 final member procedure vacation( p_days number ),
8 not instantiable member procedure give_raise( p_increase number ),
9 not instantiable member function yearly_compensation return number
10 )
11 not instantiable
12 not final
13 /
Type created.
SQL>
SQL> create or replace
2 type body employee as
3 final member procedure vacation( p_days number ) is
4 begin
5 if p_days + self.vacation_used <= 10 then
6 self.vacation_used := self.vacation_used + p_days;
7 else
8 raise_application_error(
9 -20001,
10 "You are " || to_char(p_days + self.vacation_used - 10) ||" days over your vacation limit." );
11 end if;
12 end;
13 end;
14 /
Type body created.
SQL>
SQL>
SQL> create or replace type consultant under employee(
2 hourly_rate number,
3 overriding member procedure give_raise( p_increase number ),
4 overriding member function yearly_compensation return number
5 )
6 /
Type created.
SQL>
SQL>
SQL>
SQL> create or replace
2 type body consultant as
3 overriding member procedure give_raise( p_increase number ) is
4 begin
5 self.hourly_rate := self.hourly_rate + p_increase;
6 end;
7 overriding member function yearly_compensation return number is
8 begin
9 return self.hourly_rate * 40 * 52;
10 end;
11 end;
12 /
Type body created.
SQL>
SQL> drop type consultant;
Type dropped.
SQL>
SQL> drop type employee;
Type dropped.
SQL>
</source>

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в 13:45, 26 мая 2010

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