how to make distinct type with condition in oracle - oracle

Question

create or replace TYPE PDV AS OBJECT
( percentage NUMBER(4,2),
MEMBER FUNCTION get_percentage RETURN NUMBER
) INSTANTIABLE NOT FINAL;
create or replace TYPE BODY PDV AS
MEMBER FUNCTION get_percentage RETURN NUMBER AS
BEGIN
return SELF.percentage;
END get_percentage;
END;
I have table Product (productID, name, description, percentage)
When I insert this in the database, it should be saved in the table Product:
insert into Product VALUES (1, 'Table', 'Brown table for six people.Made of oak', PDV(20.00));
When I insert this into the database, an error should occur:
insert into Product VALUES (1, 'Table', 'Brown table for six people.Made of oak', PDV(130.20));
I want to make distinct type with condition - percentage must be between 0 and 100. Where to put that condition?

Answer 1

percentage must be between 0 and 100. Where to put that condition?
Nowhere, I'd say. PERCENTAGE's data type, a numeric having precision 4 and scale 2 will take care about it.
As you didn't provide whole code you use, here's an example.
SQL> create or replace type pdv as object
2 (productid number,
3 name varchar2(30),
4 description varchar2(100),
5 percentage number(4, 2),
6 member function get_percentage return number
7 ) instantiable not final;
8 /
Type created.
SQL> create or replace type body pdv as
2 member function get_percentage return number as
3 begin
4 return self.percentage;
5 end get_percentage;
6 end;
7 /
Type body created.
SQL> create table product (prod pdv);
Table created.
SQL> insert into product values (pdv(1, 'Table', 'Made of oak', 20));
1 row created.
SQL> insert into product values (pdv(1, 'Table', 'Made of oak', 130));
insert into product values (pdv(1, 'Table', 'Made of oak', 130))
*
ERROR at line 1:
ORA-01438: value larger than specified precision allowed for this column
SQL> insert into product values (pdv(1, 'Table', 'Made of oak', 55.567));
1 row created.
SQL>
[EDIT, written after reading OP's comment]
I'm not sure I understood what you mean. If it means that you want to create an inline CHECK constraint, well, that won't work:
SQL> create or replace type pdv_typ as object
2 (
3 producid number,
4 name varchar2 (30),
5 description varchar2 (100),
6 percentage number (4, 2) constraint ch_perc check (percentage between 0 and 100),
7 member function get_percentage
8 return number
9 );
10 /
create or replace type pdv_typ as object
*
ERROR at line 1:
ORA-06545: PL/SQL: compilation error - compilation aborted
ORA-06550: line 6, column 29:
PLS-00103: Encountered the symbol "CONSTRAINT" when expecting one of the
following:
:= ) , not null default external character
ORA-06550: line 0, column 0:
PLS-00565: PDV_TYP must be completed as a potential REF target (object type)
SQL>
What you could do is to create a table whose column data type is of a previously created type, such as this:
SQL> create or replace type pdv_typ as object
2 (
3 producid number,
4 name varchar2 (30),
5 description varchar2 (100),
6 percentage number (4, 2),
7 member function get_percentage
8 return number
9 );
10 /
Type created.
SQL> create or replace type body pdv_typ
2 as
3 member function get_percentage
4 return number
5 as
6 begin
7 return self.percentage;
8 end get_percentage;
9 end;
10 /
Type body created.
SQL> create table pdv_tab
2 (
3 id number primary key,
4 pdv pdv_typ constraint ch_perc check (pdv.percentage between 0 and 100)
5 );
Table created.
SQL>
SQL> insert into pdv_tab values (1, pdv_typ (1, 'Table', 'Made of oak', 20));
1 row created.
SQL> insert into pdv_tab values (2, pdv_typ (2, 'Chair', 'Made of steel', 120));
insert into pdv_tab values (2, pdv_typ (2, 'Chair', 'Made of steel', 120))
*
ERROR at line 1:
ORA-01438: value larger than specified precision allowed for this column
SQL> insert into pdv_tab values (3, pdv_typ (3, 'Window', 'Made of glass', -5));
insert into pdv_tab values (3, pdv_typ (3, 'Window', 'Made of glass', -5))
*
ERROR at line 1:
ORA-02290: check constraint (SCOTT.CH_PERC) violated
SQL>
Personally, I really, really don't like object side of Oracle. For me, it is a relational DBMS. Object support came as if they wanted to say hey, look, we can do that too!. I can't remember whether I ever used that functionality, except for educational purposes. Drawbacks? Plenty. Benefits? None. Once again, from my point of view.
So, what are you, really, doing? This is not a real-life problem, is it? That suggests your comment, saying that it has to be done that way. Says who? If it is a client, tell him to mind his own business. If it is a professor, then do what he says, regardless.

Answer 2

The straightforward way to do this would be a CHECK constraint on the table. That could be as simple as:
create table Product (
productID number primary key
, name varchar2(30) not null
, description varchar2(128) not null
, percentage number check (percentage between 0 and 100)
);
Demo in SQL Fiddle.