Truncate giving problems.

Question

I had kept a process (PL/SQL block) running which was supposed to insert 4000000 rows in a table.
But there was no COMMIT issued inside this block.
By mistake I closed by SQL PLUS session.
Next day when I issued the TRUNCATE command it gives me the error “ORA-02266: unique/primary keys in table referenced by enabled foreign keys”
But there are no rows in this table
See the details below
Connected to:
Oracle8i Enterprise Edition Release 8.1.7.4.0 - 64bit Production
With the Partitioning option
JServer Release 8.1.7.4.0 - 64bit Production
SQL> select count(*) from calc_policy_details;
COUNT(*)
0
SQL> truncate table calc_policy_details;
truncate table calc_policy_details
ERROR at line 1:
ORA-02266: unique/primary keys in table referenced by enabled foreign keys
SQL> delete from calc_policy_details;
0 rows deleted.
SQL> truncate table calc_policy_details;
truncate table calc_policy_details
ERROR at line 1:
ORA-02266: unique/primary keys in table referenced by enabled foreign keys
SQL> select count(*) from calc_policy_details;
COUNT(*)
0

Answer 1

This is a standard error message. When Oracle does a truncate, it simply marks all blocks used by the table as being unused. The blocks above MINEXTENT are released to free space and the rest are retained in the table.
Because Oracle does not look at the data at all, this is a safeguard to avoid breaking referential integrity.
SQL> CREATE TABLE t (id number PRIMARY KEY, descr VARCHAR2(10));
Table created.
SQL> CREATE TABLE tc (c_id NUMBER, id NUMBER REFERENCES t (id),
  2                   c_descr VARCHAR2(10));
Table created.
SQL> TRUNCATE TABLE t;
TRUNCATE TABLE t
ERROR at line 1:
ORA-02266: unique/primary keys in table referenced by enabled foreign keys
but
SQL> DELETE FROM t;
0 rows deleted.TTFN
John