Category: Tricks

DECODE With Ranges

Tim Hall wrote this post yesterday (as part of Joel Kallman Day 2022) with some examples for “the old way” vs. “the new way” to do some stuff.
One of these examples is DECODE and CASE Expressions. As Tim wrote:

CASE expressions were first released in Oracle 8i […] Prior to that if we wanted something similar to a CASE expression in our SQL, we had to use the DECODE function.

This reminded me of a trick I came up with many years ago, probably before 8i 🙂

A table T has a column X, and we need a query that one of the items it returns is a rank – either “Low”, “Medium” or “High”. This rank is determined by the value of X and two thresholds – LOW_TH and HIGH_TH.

With a (Searched) CASE Expression it’s as simple as this:

select x,
       case
           when x < :low_th then
            'Low'
           when x < :high_th then
            'Medium'
           else
            'High'
       end
from   t;

But how could we do it without CASE?

One option is to write a PL/SQL function that gets X as the input and returns the rank as the output.

But could we have a pure SQL solution? DECODE doesn't look like a good fit, because it works with discrete values, not with ranges.

It is possible. We just need to convert each range to some unique discrete value. As we have 3 ranges, we need 3 values, and there is a SQL function that returns exactly 3 possible values (and was already supported back then) - the sign function.

In order to use the sign function, we first need to map the "Low" range to negative numbers, the "Medium" range to 0, and the "High" range to positive numbers.

This mapping can be done with this expression:

floor((x - :low_th) / (:high_th - :low_th))

And now it's easy to write the final query:

select x,
       decode(
         sign(floor((x - :low_th) / (:high_th - :low_th))),
           -1, 'Low',
            0, 'Medium',
            1, 'High')
from   t;

Obviously it's better having "modern" capabilities such as the CASE expression, but not having them had the advantage of forcing us to be creative 🙂

Kakuro Helper using SQL Query with PowerMultiSet and Pivot

When solving Kakuro it is essential to know for a given integer X and a given number of elements N all the combinations of N non-repeating digits [1-9] that their sum equals to X.

For example, there is only one combination for creating the number 7 from 3 elements:

1+2+4

And there are 6 combinations for creating the number 15 from 4 elements:

1+2+3+9
1+2+4+8
1+2+5+7
1+3+4+7
1+3+5+6
2+3+4+6

Let’s generate a list of all the possible Xs and Ns, using SQL of course.
What makes it really easy is the not-so-popular SQL function POWERMULTISET (available since Oracle 10g).
It is a collection function that gets a nested table and returns a collection of collections containing all nonempty subsets of the input collection.

create type integer_ntt as table of integer
/

break on x on num_of_elements skip 1

select sum(b.column_value) x,
       a.num_of_elements,
       listagg(b.column_value,'+') within group(order by b.column_value) expr
from   (select rownum id,
               column_value combination,
               cardinality(column_value) num_of_elements
        from   table(powermultiset(integer_ntt(1,2,3,4,5,6,7,8,9)))) a,
       table(a.combination) b
where  a.num_of_elements > 1
group  by a.id,a.num_of_elements
order  by x,num_of_elements,expr;

         X NUM_OF_ELEMENTS EXPR
---------- --------------- --------------------
         3               2 1+2

         4               2 1+3

         5               2 1+4
                           2+3

         6               2 1+5
                           2+4

                         3 1+2+3

         7               2 1+6
                           2+5
                           3+4

                         3 1+2+4
.
.
.
        15               2 6+9
                           7+8

                         3 1+5+9
                           1+6+8
                           2+4+9
                           2+5+8
                           2+6+7
                           3+4+8
                           3+5+7
                           4+5+6

                         4 1+2+3+9
                           1+2+4+8
                           1+2+5+7
                           1+3+4+7
                           1+3+5+6
                           2+3+4+6

                         5 1+2+3+4+5
.
.
.
        42               7 3+4+5+6+7+8+9

                         8 1+2+4+5+6+7+8+9

        43               8 1+3+4+5+6+7+8+9

        44               8 2+3+4+5+6+7+8+9

        45               9 1+2+3+4+5+6+7+8+9

502 rows selected.

We can get a more user-friendly output by pivoting the results into a matrix, where one axis is X, the second axis is N, and each cell contains all the combinations for this X|N pair.
This can be done easily using the PIVOT operator (available since Oracle 11g):

break on x skip 1
col 2 format a4
col 3 format a6
col 4 format a8
col 5 format a10
col 6 format a12
col 7 format a14
col 8 format a16
col 9 format a18

select *
from   (select sum(b.column_value) x,
               a.num_of_elements,
               listagg(b.column_value, '+') within group(order by b.column_value) expr
        from   (select rownum id,
                       column_value combination,
                       cardinality(column_value) num_of_elements
                from   table(powermultiset(integer_ntt(1,2,3,4,5,6,7,8,9)))) a,
               table(a.combination) b
        where  a.num_of_elements > 1
        group  by a.id,
                  a.num_of_elements)
pivot (listagg(expr, chr(10)) within group (order by expr)
      for num_of_elements in(2,3,4,5,6,7,8,9));

         X 2    3      4        5          6            7              8                9
---------- ---- ------ -------- ---------- ------------ -------------- ---------------- ------------------
         3 1+2

         4 1+3

         5 1+4
           2+3


         6 1+5  1+2+3
           2+4


         7 1+6  1+2+4
           2+5
           3+4


         8 1+7  1+2+5
           2+6  1+3+4
           3+5


         9 1+8  1+2+6
           2+7  1+3+5
           3+6  2+3+4
           4+5


        10 1+9  1+2+7  1+2+3+4
           2+8  1+3+6
           3+7  1+4+5
           4+6  2+3+5


        11 2+9  1+2+8  1+2+3+5
           3+8  1+3+7
           4+7  1+4+6
           5+6  2+3+6
                2+4+5


        12 3+9  1+2+9  1+2+3+6
           4+8  1+3+8  1+2+4+5
           5+7  1+4+7
                1+5+6
                2+3+7
                2+4+6
                3+4+5


        13 4+9  1+3+9  1+2+3+7
           5+8  1+4+8  1+2+4+6
           6+7  1+5+7  1+3+4+5
                2+3+8
                2+4+7
                2+5+6
                3+4+6


        14 5+9  1+4+9  1+2+3+8
           6+8  1+5+8  1+2+4+7
                1+6+7  1+2+5+6
                2+3+9  1+3+4+6
                2+4+8  2+3+4+5
                2+5+7
                3+4+7
                3+5+6


        15 6+9  1+5+9  1+2+3+9  1+2+3+4+5
           7+8  1+6+8  1+2+4+8
                2+4+9  1+2+5+7
                2+5+8  1+3+4+7
                2+6+7  1+3+5+6
                3+4+8  2+3+4+6
                3+5+7
                4+5+6


        16 7+9  1+6+9  1+2+4+9  1+2+3+4+6
                1+7+8  1+2+5+8
                2+5+9  1+2+6+7
                2+6+8  1+3+4+8
                3+4+9  1+3+5+7
                3+5+8  1+4+5+6
                3+6+7  2+3+4+7
                4+5+7  2+3+5+6


        17 8+9  1+7+9  1+2+5+9  1+2+3+4+7
                2+6+9  1+2+6+8  1+2+3+5+6
                2+7+8  1+3+4+9
                3+5+9  1+3+5+8
                3+6+8  1+3+6+7
                4+5+8  1+4+5+7
                4+6+7  2+3+4+8
                       2+3+5+7
                       2+4+5+6


        18      1+8+9  1+2+6+9  1+2+3+4+8
                2+7+9  1+2+7+8  1+2+3+5+7
                3+6+9  1+3+5+9  1+2+4+5+6
                3+7+8  1+3+6+8
                4+5+9  1+4+5+8
                4+6+8  1+4+6+7
                5+6+7  2+3+4+9
                       2+3+5+8
                       2+3+6+7
                       2+4+5+7
                       3+4+5+6


        19      2+8+9  1+2+7+9  1+2+3+4+9
                3+7+9  1+3+6+9  1+2+3+5+8
                4+6+9  1+3+7+8  1+2+3+6+7
                4+7+8  1+4+5+9  1+2+4+5+7
                5+6+8  1+4+6+8  1+3+4+5+6
                       1+5+6+7
                       2+3+5+9
                       2+3+6+8
                       2+4+5+8
                       2+4+6+7
                       3+4+5+7


        20      3+8+9  1+2+8+9  1+2+3+5+9
                4+7+9  1+3+7+9  1+2+3+6+8
                5+6+9  1+4+6+9  1+2+4+5+8
                5+7+8  1+4+7+8  1+2+4+6+7
                       1+5+6+8  1+3+4+5+7
                       2+3+6+9  2+3+4+5+6
                       2+3+7+8
                       2+4+5+9
                       2+4+6+8
                       2+5+6+7
                       3+4+5+8
                       3+4+6+7


        21      4+8+9  1+3+8+9  1+2+3+6+9  1+2+3+4+5+6
                5+7+9  1+4+7+9  1+2+3+7+8
                6+7+8  1+5+6+9  1+2+4+5+9
                       1+5+7+8  1+2+4+6+8
                       2+3+7+9  1+2+5+6+7
                       2+4+6+9  1+3+4+5+8
                       2+4+7+8  1+3+4+6+7
                       2+5+6+8  2+3+4+5+7
                       3+4+5+9
                       3+4+6+8
                       3+5+6+7


        22      5+8+9  1+4+8+9  1+2+3+7+9  1+2+3+4+5+7
                6+7+9  1+5+7+9  1+2+4+6+9
                       1+6+7+8  1+2+4+7+8
                       2+3+8+9  1+2+5+6+8
                       2+4+7+9  1+3+4+5+9
                       2+5+6+9  1+3+4+6+8
                       2+5+7+8  1+3+5+6+7
                       3+4+6+9  2+3+4+5+8
                       3+4+7+8  2+3+4+6+7
                       3+5+6+8
                       4+5+6+7


        23      6+8+9  1+5+8+9  1+2+3+8+9  1+2+3+4+5+8
                       1+6+7+9  1+2+4+7+9  1+2+3+4+6+7
                       2+4+8+9  1+2+5+6+9
                       2+5+7+9  1+2+5+7+8
                       2+6+7+8  1+3+4+6+9
                       3+4+7+9  1+3+4+7+8
                       3+5+6+9  1+3+5+6+8
                       3+5+7+8  1+4+5+6+7
                       4+5+6+8  2+3+4+5+9
                                2+3+4+6+8
                                2+3+5+6+7


        24      7+8+9  1+6+8+9  1+2+4+8+9  1+2+3+4+5+9
                       2+5+8+9  1+2+5+7+9  1+2+3+4+6+8
                       2+6+7+9  1+2+6+7+8  1+2+3+5+6+7
                       3+4+8+9  1+3+4+7+9
                       3+5+7+9  1+3+5+6+9
                       3+6+7+8  1+3+5+7+8
                       4+5+6+9  1+4+5+6+8
                       4+5+7+8  2+3+4+6+9
                                2+3+4+7+8
                                2+3+5+6+8
                                2+4+5+6+7


        25             1+7+8+9  1+2+5+8+9  1+2+3+4+6+9
                       2+6+8+9  1+2+6+7+9  1+2+3+4+7+8
                       3+5+8+9  1+3+4+8+9  1+2+3+5+6+8
                       3+6+7+9  1+3+5+7+9  1+2+4+5+6+7
                       4+5+7+9  1+3+6+7+8
                       4+6+7+8  1+4+5+6+9
                                1+4+5+7+8
                                2+3+4+7+9
                                2+3+5+6+9
                                2+3+5+7+8
                                2+4+5+6+8
                                3+4+5+6+7


        26             2+7+8+9  1+2+6+8+9  1+2+3+4+7+9
                       3+6+8+9  1+3+5+8+9  1+2+3+5+6+9
                       4+5+8+9  1+3+6+7+9  1+2+3+5+7+8
                       4+6+7+9  1+4+5+7+9  1+2+4+5+6+8
                       5+6+7+8  1+4+6+7+8  1+3+4+5+6+7
                                2+3+4+8+9
                                2+3+5+7+9
                                2+3+6+7+8
                                2+4+5+6+9
                                2+4+5+7+8
                                3+4+5+6+8


        27             3+7+8+9  1+2+7+8+9  1+2+3+4+8+9
                       4+6+8+9  1+3+6+8+9  1+2+3+5+7+9
                       5+6+7+9  1+4+5+8+9  1+2+3+6+7+8
                                1+4+6+7+9  1+2+4+5+6+9
                                1+5+6+7+8  1+2+4+5+7+8
                                2+3+5+8+9  1+3+4+5+6+8
                                2+3+6+7+9  2+3+4+5+6+7
                                2+4+5+7+9
                                2+4+6+7+8
                                3+4+5+6+9
                                3+4+5+7+8


        28             4+7+8+9  1+3+7+8+9  1+2+3+5+8+9  1+2+3+4+5+6+7
                       5+6+8+9  1+4+6+8+9  1+2+3+6+7+9
                                1+5+6+7+9  1+2+4+5+7+9
                                2+3+6+8+9  1+2+4+6+7+8
                                2+4+5+8+9  1+3+4+5+6+9
                                2+4+6+7+9  1+3+4+5+7+8
                                2+5+6+7+8  2+3+4+5+6+8
                                3+4+5+7+9
                                3+4+6+7+8


        29             5+7+8+9  1+4+7+8+9  1+2+3+6+8+9  1+2+3+4+5+6+8
                                1+5+6+8+9  1+2+4+5+8+9
                                2+3+7+8+9  1+2+4+6+7+9
                                2+4+6+8+9  1+2+5+6+7+8
                                2+5+6+7+9  1+3+4+5+7+9
                                3+4+5+8+9  1+3+4+6+7+8
                                3+4+6+7+9  2+3+4+5+6+9
                                3+5+6+7+8  2+3+4+5+7+8


        30             6+7+8+9  1+5+7+8+9  1+2+3+7+8+9  1+2+3+4+5+6+9
                                2+4+7+8+9  1+2+4+6+8+9  1+2+3+4+5+7+8
                                2+5+6+8+9  1+2+5+6+7+9
                                3+4+6+8+9  1+3+4+5+8+9
                                3+5+6+7+9  1+3+4+6+7+9
                                4+5+6+7+8  1+3+5+6+7+8
                                           2+3+4+5+7+9
                                           2+3+4+6+7+8


        31                      1+6+7+8+9  1+2+4+7+8+9  1+2+3+4+5+7+9
                                2+5+7+8+9  1+2+5+6+8+9  1+2+3+4+6+7+8
                                3+4+7+8+9  1+3+4+6+8+9
                                3+5+6+8+9  1+3+5+6+7+9
                                4+5+6+7+9  1+4+5+6+7+8
                                           2+3+4+5+8+9
                                           2+3+4+6+7+9
                                           2+3+5+6+7+8


        32                      2+6+7+8+9  1+2+5+7+8+9  1+2+3+4+5+8+9
                                3+5+7+8+9  1+3+4+7+8+9  1+2+3+4+6+7+9
                                4+5+6+8+9  1+3+5+6+8+9  1+2+3+5+6+7+8
                                           1+4+5+6+7+9
                                           2+3+4+6+8+9
                                           2+3+5+6+7+9
                                           2+4+5+6+7+8


        33                      3+6+7+8+9  1+2+6+7+8+9  1+2+3+4+6+8+9
                                4+5+7+8+9  1+3+5+7+8+9  1+2+3+5+6+7+9
                                           1+4+5+6+8+9  1+2+4+5+6+7+8
                                           2+3+4+7+8+9
                                           2+3+5+6+8+9
                                           2+4+5+6+7+9
                                           3+4+5+6+7+8


        34                      4+6+7+8+9  1+3+6+7+8+9  1+2+3+4+7+8+9
                                           1+4+5+7+8+9  1+2+3+5+6+8+9
                                           2+3+5+7+8+9  1+2+4+5+6+7+9
                                           2+4+5+6+8+9  1+3+4+5+6+7+8
                                           3+4+5+6+7+9


        35                      5+6+7+8+9  1+4+6+7+8+9  1+2+3+5+7+8+9
                                           2+3+6+7+8+9  1+2+4+5+6+8+9
                                           2+4+5+7+8+9  1+3+4+5+6+7+9
                                           3+4+5+6+8+9  2+3+4+5+6+7+8


        36                                 1+5+6+7+8+9  1+2+3+6+7+8+9  1+2+3+4+5+6+7+8
                                           2+4+6+7+8+9  1+2+4+5+7+8+9
                                           3+4+5+7+8+9  1+3+4+5+6+8+9
                                                        2+3+4+5+6+7+9


        37                                 2+5+6+7+8+9  1+2+4+6+7+8+9  1+2+3+4+5+6+7+9
                                           3+4+6+7+8+9  1+3+4+5+7+8+9
                                                        2+3+4+5+6+8+9


        38                                 3+5+6+7+8+9  1+2+5+6+7+8+9  1+2+3+4+5+6+8+9
                                                        1+3+4+6+7+8+9
                                                        2+3+4+5+7+8+9


        39                                 4+5+6+7+8+9  1+3+5+6+7+8+9  1+2+3+4+5+7+8+9
                                                        2+3+4+6+7+8+9


        40                                              1+4+5+6+7+8+9  1+2+3+4+6+7+8+9
                                                        2+3+5+6+7+8+9


        41                                              2+4+5+6+7+8+9  1+2+3+5+6+7+8+9

        42                                              3+4+5+6+7+8+9  1+2+4+5+6+7+8+9

        43                                                             1+3+4+5+6+7+8+9

        44                                                             2+3+4+5+6+7+8+9

        45                                                                              1+2+3+4+5+6+7+8+9


43 rows selected.

impdp – which rows failed?

Since version 11.1, Data Pump Import supports the SKIP_CONSTRAINT_ERRORS option, which specifies that you want the import operation to proceed even if (non-deferred) constraint violations are encountered. It logs any rows that cause constraint violations, but does not stop, and does load the other rows. If SKIP_CONSTRAINT_ERRORS is not set, then the default behavior is to roll back the entire load of the data object on which constraint violations are encountered.

For example:

The table presidents was created by the following statement:

create table presidents (
  id         number       primary key,
  first_name varchar2(20),
  last_name  varchar2(20)
);

and is currently containing the following data:

        ID FIRST_NAME           LAST_NAME
---------- -------------------- --------------------
         1 George               Washington
         2 John                 Adams
         3 Thomas               Jefferson
         4 James                Madison
         5 James                Monroe
         6 John Quincy          Adams
         7 Andrew               Jackson
         8 Martin               Van Buren

We have a dump file that contains an export of the presidents table (from somewhere else or from some previous point in time), and we’d like to append the data from the dump file to the table.
The dump file contains the following data:

        ID FIRST_NAME           LAST_NAME
---------- -------------------- --------------------
         7 William              Harrison
         8 John                 Tyler
         9 James                Polk
        10 Zachary              Taylor
        11 Millard              Fillmore
        12 Franklin             Pierce

Obviously, the records with ID 7 and 8 cannot be added to the table, because a primary key constraint is defined on the ID column, and the table already contains records with these ID values.

If we try to execute the following import, without the SKIP_CONSTRAINT_ERRORS option, we will get an error and the whole operation will be rolled back:

impdp oren/oren tables=presidents dumpfile=presidents.dmp table_exists_action=append logfile=presidents_imp1.log

Import: Release 11.2.0.4.0 - Production on Fri Jul 18 19:33:33 2014
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 11g Release 11.2.0.1.0 - 64bit Production
 Master table "OREN"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
 Starting "OREN"."SYS_IMPORT_TABLE_01": oren/******** tables=presidents dumpfile=presidents.dmp table_exists_action=append logfile=presidents_imp1.log
 Processing object type TABLE_EXPORT/TABLE/TABLE
 ORA-39152: Table "OREN"."PRESIDENTS" exists. Data will be appended to existing table but all dependent metadata will be skipped due to table_exists_action of append
 Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
 ORA-31693: Table data object "OREN"."PRESIDENTS" failed to load/unload and is being skipped due to error:
 ORA-00001: unique constraint (OREN.SYS_C0023857) violated
 Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
 Job "OREN"."SYS_IMPORT_TABLE_01" completed with 2 error(s) at 16:33:35

As expected, if we check the contents of the table we see that no records have been added from the dump file:

select * from presidents;

        ID FIRST_NAME           LAST_NAME
---------- -------------------- --------------------
         1 George               Washington
         2 John                 Adams
         3 Thomas               Jefferson
         4 James                Madison
         5 James                Monroe
         6 John Quincy          Adams
         7 Andrew               Jackson
         8 Martin               Van Buren

Now let’s execute the import with the SKIP_CONSTRAINT_ERRORS option:

impdp oren/oren tables=presidents dumpfile=presidents.dmp table_exists_action=append logfile=presidents_imp2.log data_options=SKIP_CONSTRAINT_ERRORS

Import: Release 11.2.0.4.0 - Production on Fri Jul 18 19:38:00 2014

Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.

Connected to: Oracle Database 11g Release 11.2.0.1.0 - 64bit Production
Master table "OREN"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "OREN"."SYS_IMPORT_TABLE_01": oren/******** tables=presidents dumpfile=presidents.dmp table_exists_action=append logfile=presidents_imp2.log data_options=SKIP_CONSTRAINT_ERRORS
Processing object type TABLE_EXPORT/TABLE/TABLE
ORA-39152: Table "OREN"."PRESIDENTS" exists. Data will be appended to existing table but all dependent metadata will be skipped due to table_exists_action of append
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "OREN"."PRESIDENTS" 5.945 KB 4 out of 6 rows
2 row(s) were rejected with the following error:
ORA-00001: unique constraint (OREN.SYS_C0023857) violated

Rejected rows with the primary keys are:
Rejected row #1:
column ID: 7
Rejected row #2:
column ID: 8
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
Job "OREN"."SYS_IMPORT_TABLE_01" completed with 1 error(s) at 16:38:06

We see that 4 rows were imported and that 2 rows were rejected due to unique constraint violation. We can also see from the log which rows were rejected, or more precisely, what are the primary key values of the rejected rows.

But what if we want to know the values of the other columns in the rejected rows?
I don’t know about such a feature, but I made some “digging” and succeeded to come out with a solution.

First I looked at the statements that Data Pump did behind the scenes (by querying V$SQL), and one of the statements I found was this:

INSERT INTO "OREN"."ERR$DP004BC9640001" (
  ORA_ERR_NUMBER$, ORA_ERR_MESG$, ORA_ERR_ROWID$, ORA_ERR_OPTYP$, ORA_ERR_TAG$,
  "ID", "FIRST_NAME", "LAST_NAME")
VALUES (:1, :2, :3, :4, :5, :6, :7, :8)

So apparently Data Pump simply uses DML Error Logging to support the SKIP_CONSTRAINT_ERRORS option. And this means that the values of all the columns (except for LOBs etc.) of the rejected rows are basically available. All we need to do is to select from this ERR$DP004BC9640001 table, right?
Well, there are two problems with this:

  • The name of the table is not consistent. I ran it several times and got a different name in each run (but it always started with ERR$DP).
  • The ERR$DP… table is dropped as soon as the import is done, so by the time we want to select from it, it is already gone.

But we can overcome these issues, with the following flow:

1. Before starting the import process, open a SQL*Plus session and execute:

lock table presidents in share mode;

and keep this session (and transaction) open. This will block the import process (as well as any other process!) when it tries to insert records into the table, and will give us the opportunity to check the name of the error logging table, which, as we’ll see, will already exist at that point in time.

2. Start the import:

impdp oren/oren tables=presidents dumpfile=presidents.dmp table_exists_action=append logfile=presidents_imp.log data_options=SKIP_CONSTRAINT_ERRORS

Import: Release 11.2.0.4.0 - Production on Fri Jul 18 23:13:14 2014

Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.

Connected to: Oracle Database 11g Release 11.2.0.1.0 - 64bit Production
Master table "OREN"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "OREN"."SYS_IMPORT_TABLE_01": oren/******** tables=presidents dumpfile=presidents.dmp table_exists_action=append logfile=presidents_imp.log data_options=SKIP_CONSTRAINT_ERRORS
Processing object type TABLE_EXPORT/TABLE/TABLE
ORA-39152: Table "OREN"."PRESIDENTS" exists. Data will be appended to existing table but all dependent metadata will be skipped due to table_exists_action of append
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA

3. The import is blocked now. Going back to the SQL*Plus session, let’s find out the error logging table name:

select table_name from user_tables where table_name like 'ERR$DP%';

TABLE_NAME
-----------------------
ERR$DP0047ABBF0001

4. Start a second SQL*Plus session and lock the error logging table in a mode that will allow the import to fill it but not to drop it:

lock table ERR$DP0047ABBF0001 in row share mode;

5. In the first SQL*Plus session, release the lock on the presidents table so the import can continue:

Rollback;

And the import continues:

. . imported "OREN"."PRESIDENTS" 5.945 KB 4 out of 6 rows
2 row(s) were rejected with the following error:
ORA-00001: unique constraint (OREN.SYS_C0023889) violated

Rejected rows with the primary keys are:
Rejected row #1:
column ID: 7
Rejected row #2:
column ID: 8
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
Job "OREN"."SYS_IMPORT_TABLE_01" completed with 1 error(s) at 20:35:21

6. When the import is done, we can see all the rejected rows from one of the SQL*Plus sessions:

select id,first_name,last_name from ERR$DP0047ABBF0001;

ID  FIRST_NAME           LAST_NAME
--- -------------------- --------------------
7   William              Harrison
8   John                 Tyler

7. And finally, to cleanup, we can drop the error logging table from the second SQL*Plus session:

drop table ERR$DP0047ABBF0001;

You are most welcome to comment or to ask questions in this page, or to write me at oren@db-oriented.com.