Answer / saraswathi muthuraman

Oracle will have a default table called 'DUAL'.
Dual table will have only one column "DUMMY". U cann't
insert values into dual table. By default, a row will
existing in dual table.

SQL> desc dual;
DUMMY varchar2(1)

SQL> select * from dual;

X

1 row selected.

SQL> insert into dual values (10);
insert into dual values (10)
*
ERROR at line 1:
ORA-01031: insufficient privileges


U can create you own table with the name of dual.

SQL> create table dual(xy number,zz number);

Table created.

SQL> desc dual;
xy number
zz number

u can insert values in you own dual table.

Answer / eshwari

Dual table is a sample permanent table which come along with
oracle.
for example if u want to knw the sin(45) value then u have
to retreave it from a table.but there is no table to
retreave that value.
so we use the sample table dual as table name in place of
table name in the select query.

ex:select sin(45) from dual;

select trunc(round(156.00,-1),-1) from dual;

2 Answers  

---

What happens if variable names collide with table/column names?

0 Answers  

---

How many anonymous blocks can be defined?

0 Answers  

---

How to assign a table row to a record variable?

0 Answers  

---

What is the use of file param in imp command?

0 Answers  

---

Create table Employee ( Employee_Id varchar2(8) Constraint emp_id_pk primary key, FirstName varchar2(50), LastName varchar2(50), DeptID Number(5) Constraint dept_id_fk Foreign Key(DeptId) References Department(DeptId) ) Error I am getting: Constraint specification are not allowed here

2 Answers  

---

What happens if the update subquery returns multiple rows?

0 Answers  

---

Where do you use decode and case statements?

0 Answers  

---

In XIR2 if we lost the administration password .How can we regain the password?thanks in advance.

0 Answers   IBM,

---

What are the sql clauses supported in the link property sheet ?

1 Answers   Oracle,

---

What is a snapshot in oracle database?

0 Answers  

---

What are the Limitations of a CHECK Constraint ?

5 Answers  

---