Question

I just have an odd question. I know it may be funny but I just have a curiosity about this.
Here is my question in detail:

Suppose there is a column in database named ‘gender’ that has boolean value i.e. either 0 or 1. 0=Male and 1=Female.
Now when we display data of a form that has this type of field, we have to do code, that (gender=0)?Male:Female.

Now I just want to know if sql provide any way, where automatically when a Record Set is generated, all gender value is replaced by Male or Female automatically. i.e. no need of this one line code?

Answer 1

aside from case/decode which others have shown, in 11gR1 onwards we can have a virtual Column.

SQL> create table test(name varchar2(20), gender number(1));

Table created.

SQL> insert into test values ('Paul', 0);

1 row created.

SQL> insert into test values ('Vicky', 1);

1 row created.

SQL> commit;

Commit complete.

SQL> alter table test add (gender_str varchar2(6) generated always as (case gender when 0 then 'Male' when 1 then 'Female' end));

Table altered.

SQL> select * from test;

NAME                                         GENDER GENDER
-------------------- ------------------------------ ------
Paul                                              0 Male
Vicky                                             1 Female

you can index virtual columns too if you so desire.