Question

I am asked to to add a constraint for an attribute in the table so that the value of the attribute should be a float number between 0 and 1. As far as I know, float(a,b) is not here for the task….. So is there an easier way other than writing a trigger for this problem in Oracle?

Answer 1

yes use a check constraint.

SQL> alter table test modify id check (id between 0 and 1);

Table altered.

SQL> insert into test values (1.0);

1 row created.

SQL> insert into test values (1.01);
insert into test values (1.01)
*
ERROR at line 1:
ORA-02290: check constraint (SYS.SYS_C0013632) violated

you can name the check constraint if you want:

SQL> alter table test modify id constraint id_between_0_1 check (id between 0 and 1);

Table altered.

SQL> insert into test values (1.01);
insert into test values (1.01)
*
ERROR at line 1:
ORA-02290: check constraint (SYS.ID_BETWEEN_0_1) violated