Oracle PL/SQL/Object Oriented Database/treat — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
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(нет различий)
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Версия 13:45, 26 мая 2010
Treat type as
SQL>
SQL>
SQL> create or replace
2 type person as object (
3 first_name varchar2(100),
4 last_name varchar2(100),
5 dob date,
6 phone varchar2(100),
7 member function get_last_name return varchar2,
8 member function get_phone_number return varchar2 )
9 not final
10 /
Type created.
SQL>
SQL>
SQL> create or replace
2 type body person as
3 member function get_last_name return varchar2 is
4 begin
5 return self.last_name;
6 end;
7 member function get_phone_number return varchar2 is
8 begin
9 return self.phone;
10 end;
11 end;
12 /
Type body created.
SQL>
SQL> create table person_table( p person );
Table created.
SQL>
SQL>
SQL>
SQL> create or replace
2 type new_employee under person (
3 empno number,
4 hiredate date,
5 work_phone varchar2(100),
6 overriding member function get_phone_number return varchar2,
7 member function get_home_phone_number return varchar2 )
8 not final
9 /
Type created.
SQL>
SQL> create or replace
2 type body new_employee as
3 overriding member function get_phone_number return varchar2 is
4 begin
5 return self.work_phone;
6 end;
7 member function get_home_phone_number return varchar2 is
8 begin
9 return self.phone;
10 end;
11 end;
12 /
Type body created.
SQL>
SQL>
SQL> select treat( x.p as new_employee ).empno empno,
2 x.p.last_name last_name
3 from person_table x
4 where p is of ( new_employee )
5 /
no rows selected
SQL>
SQL> select * from person_table;
no rows selected
SQL>
SQL> drop table person_table;
Table dropped.
SQL>
SQL> drop type new_employee;
Type dropped.
SQL>
SQL> drop type person;
Type dropped.
SQL>
SQL>
Use treat to convert varible to a type in select statement
SQL>
SQL>
SQL>
SQL> create or replace
2 type person as object (
3 first_name varchar2(100),
4 last_name varchar2(100),
5 dob date,
6 phone varchar2(100),
7 member function get_last_name return varchar2,
8 member function get_phone_number return varchar2 )
9 not final
10 /
Type created.
SQL>
SQL>
SQL> create or replace
2 type body person as
3 member function get_last_name return varchar2 is
4 begin
5 return self.last_name;
6 end;
7 member function get_phone_number return varchar2 is
8 begin
9 return self.phone;
10 end;
11 end;
12 /
Type body created.
SQL>
SQL> create table person_table( p person );
Table created.
SQL>
SQL> select treat( p as person).get_last_name() from person_table p;
no rows selected
SQL>
SQL> drop table person_table;
Table dropped.
SQL>
SQL> drop type person;
Type dropped.
SQL>