PK contraint not disabling

Question

Hi,
We have a table A with a primary key on COL1 char(6), COL2 varchar2(100)
The current values COL1 hold are '012345','12345','09876',........
We want to change COL1 data type to numberFor this
We take a backup of table A
We disable the PK
We delete the data in table A
We change the data type of COL1Problem:
Once we insert back into table A from the backup table we get
ERROR at line 1:
ORA-00001: unique constraint (USER.A.PK) violated
If the index is disabled, why this error is happening?
Appreciate your help.
Regards,

Answer 1

I don't think you are disabling the correct (primary key) constraint. Not sure which constraint "PK" is in the following statement:
alter table A disable constraint PKWhat happens if you use the following statement instead ?
alter table A disable constraint A_PK;-- Also, answer to your earlier question - when you disable a primary key constraint, the constraint remains in the data dictionary in "disabled" state, but the primary key index associated with that constraint is dropped.
Have a look at the following sequence of statements:
test@ORA92>
test@ORA92>
test@ORA92> --
test@ORA92> drop table a;
Table dropped.
test@ORA92>
test@ORA92> -- create table a and primary key
test@ORA92> create table a (col1 char(6), col2 varchar2(100));
Table created.
test@ORA92> alter table a add constraint pk_a primary key (col1);
Table altered.
test@ORA92>
test@ORA92> -- check user_constraints and user_cons_columns
test@ORA92> select a.table_name, a.constraint_name, a.constraint_type, a.status, b.column_name, b.position
  2  from user_constraints a, user_cons_columns b
  3  where a.owner = b.owner
  4  and a.constraint_name = b.constraint_name
  5  and a.table_name = b.table_name
  6  and a.table_name = 'A';
TABLE_NAME                     CONSTRAINT_NAME                C STATUS   COLUMN_NAME            POSITION
A PK_A P ENABLED COL1 1
test@ORA92>
test@ORA92> -- check user_indexes and user_ind_columns
test@ORA92> select a.table_name, a.index_name, a.index_type, a.uniqueness, b.column_name, b.column_position
  2  from user_indexes a, user_ind_columns b
  3  where a.index_name = b.index_name
  4  and a.table_name = b.table_name
  5  and a.table_name = 'A';
TABLE_NAME                     INDEX_NAME                     INDEX_TYPE                  UNIQUENES COLUMN_NAME          COLUMN_POSITION
A                              PK_A                           NORMAL                      UNIQUE    COL1                               1
test@ORA92>
test@ORA92> -- populate table a
test@ORA92> insert into a (col1) values ('012345');
1 row created.
test@ORA92> insert into a (col1) values ('12345');
1 row created.
test@ORA92> insert into a (col1) values ('09876');
1 row created.
test@ORA92> commit;
Commit complete.
test@ORA92>
test@ORA92> select * from a;
COL1   COL2
012345
12345
09876
test@ORA92>
test@ORA92> -- Now disable the primary key constraint
test@ORA92> alter table a disable constraint pk_a;
Table altered.
test@ORA92>
test@ORA92> -- check user_constraints and user_cons_columns
test@ORA92> select a.table_name, a.constraint_name, a.constraint_type, a.status, b.column_name, b.position
  2  from user_constraints a, user_cons_columns b
  3  where a.owner = b.owner
  4  and a.constraint_name = b.constraint_name
  5  and a.table_name = b.table_name
  6  and a.table_name = 'A';
TABLE_NAME                     CONSTRAINT_NAME                C STATUS   COLUMN_NAME            POSITION
A PK_A P DISABLED COL1 1
test@ORA92>
test@ORA92> -- check user_indexes and user_ind_columns
test@ORA92> select a.table_name, a.index_name, a.index_type, a.uniqueness, b.column_name, b.column_position
  2  from user_indexes a, user_ind_columns b
  3  where a.index_name = b.index_name
  4  and a.table_name = b.table_name
  5  and a.table_name = 'A';
no rows selected
test@ORA92>
test@ORA92>pratz