[Mrs Chepeni]

1.What is the fastest query u can execute for just checking to c if a value exists in a certain column on a certain table?
2.Can a foreign key reference a field which is not a UNIQUE or a PRIMARY KEY?
3.Can v call atored function in the contraint of a table?

[Mrs Chepeni]

The third question is
Can v call stored function in the constraint of a table?
Few more Questions...
can a named notation be used while passing parameters to a stored function called in a SQL stmt?

[Mrs Chepeni]

Answer to 2nd question

NO

If v try to add a foreign key constraint which references a field that is neither unique nor primary key then v get the following error.

SQL> alter table emp1 add constraint dname_fk foreign key(dname) references dept(dname);
alter table emp1 add constraint dname_fk foreign key(dname) references dept(dname)
*
ERROR at line 1:
ORA-02270: no matching unique or primary key for this column-list

can a named notation be used while passing parameters to a stored function called in a SQL stmt?
NO...When calling stored functions from SQL, named notation is not supported.

Answer to First Question

1.What is the fastest query u can execute for just checking to c if a value exists in a certain column on a certain table?
If there is no value then
SQL> select 'X' from dual where exists (select 'X' from emp where deptno=40);
no rows selected
If there is atleast one value then
1* select 'X' from dual where exists (select 'X' from emp where deptno=30)
SQL> /
'
-
X

Answer to third question
Can v call stored function in the constraint of a table?
NO..it will not recognise function and it will give invalid identifier.
I wrote one function and tried to use it in check constraint and it gave invalid identifier error.

[talamanchi2000]

Hi sir this is sabarinath i want to join the course oracle pl/sql plz suggest me which books are preferable.and also send me material and faqs on pl/sql

Thank u sir
your's
Sabarinathbabu