Partitioning (range) a table values less than 'A'

Question

i am referring
http://docs.oracle.com/cd/B10501_01/server.920/a96524/c12parti.htm
http://docs.oracle.com/cd/B19306_01/server.102/b14220/partconc.htm
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
"CORE     10.2.0.1.0     Production"
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
create table drop_it as select * from mv_prod_search_det2;     
CREATE TABLE DROP_IT_P(
PROD_DETAILS VARCHAR2(1000 BYTE),
     SIGN VARCHAR2(42 BYTE)
PARTITION BY RANGE(PROD_DETAILS)
PARTITION MAX_VALUE VALUES LESS THAN (MAXVALUE)
update drop_it set prod_details=upper(prod_details);     
72000 rows updated
ALTER TABLE drop_it_p EXCHANGE PARTITION MAX_VALUE WITH TABLE drop_it WITH VALIDATION;     
select * from mv_prod_search_det2
72000 rows selected
exec dbms_stats.gather_database_stats;
select * from drop_it_p partition(max_value)
ALTER TABLE DROP_IT_P
  SPLIT PARTITION MAX_VALUE AT ('B%')
  INTO (PARTITION p_a,
        PARTITION MAX_VALUE);     
select * from drop_it_p partition(p_a);
6785 rows selected
select * from drop_it_p partition(p_a) where prod_details not like 'A%'     
696 rows selectedit even shows me values that start with W,V,I,1,2,3,4,24,5 etc
although the number is less(696out of 6785) this is undesired
please help me eliminate these rows
thank you
this thread is related to tuning regexp_like by author 946207
please refer
tuning regexp_like
and partitioning a table by 946207
Edited by: 946207 on Dec 2, 2012 1:52 AM
Edited by: 946207 on Dec 2, 2012 11:02 PM

Answer 1

First, when you post related threads you should cross-link them so people have access to all of the information about the problem you are trying to work with.
partitioning a table
>
it even shows me values that start with W,V,I,1,2,3,4,24,5 etc
although the number is less(696out of 6785) this is undesired
>
Yes - that is what it should be doing.
These are the steps you took to populate the table
1. You originally inserted ALL data into table 'drop_it' with no restriction on the PROD_DETAILS values.
create table drop_it as select * from mv_prod_search_det2;     2. Then you converted the PROD_DETAILS value to upper case. That has no effect on numbers or other non-alphabetic characters.
update drop_it set prod_details=upper(prod_details);3. Then you create a new table with only one partition using MAXVALUe
PROD_DETAILS VARCHAR2(1000 BYTE),
     SIGN VARCHAR2(42 BYTE)
PARTITION BY RANGE(PROD_DETAILS)
PARTITION MAX_VALUE VALUES LESS THAN (MAXVALUE)
);4. Then you populate the partitioned table by exchange. It now has the same data including the numeric data.
ALTER TABLE drop_it_p EXCHANGE PARTITION MAX_VALUE WITH TABLE drop_it WITH VALIDATION;     5. Then you split the one MAXVALUE partition into two partitions. One with data < 'B%' and one with the remaining data that sorts higher based on your character set.
ALTER TABLE DROP_IT_P
  SPLIT PARTITION MAX_VALUE AT ('B%')
  INTO (PARTITION p_a,
        PARTITION MAX_VALUE);     The split on 'B%' when creating partition p_a is equivalent to you 'WITH VALUES < 'B%'. Since PROD_DETAILS is a VARCHAR2 datatype that 'LESS THAN' comparison uses the character order based on your database character set and most, if not all, character sets have characters that sort lower than the uppercase alphabetic characters.
For example in the ASCII character set an uppercase 'A' is decimal 65 so 64 other characters (including the digitis 0-9) sort lower than 'A'.
http://www.asciitable.com/
As the doc you cited shows
>
•All partitions, except the first, have an implicit lower bound specified by the VALUES LESS THAN clause on the previous partition.
>
That 'first' partition has no lower bound so ALL data, including digits, that sort less than 'B%' will be in that partition.
>
please help me eliminate these rows
>
Either don't select the data to begin with or remove it using a simple DELETE query. Also you can do the case conversion when you select the data.
create table drop_it as select upper(prod_details) prod_details, sign from mv_prod_search_det2 where upper(prod_details >= 'A';Before you do that you should make sure you define the actual business rule you want to use to define the data you really want to keep and exclude.
Because most, if not all, character sets also have characters that sort HIGHER than the alphabetic characters. That ASCII table shows five of them. If you don't filter them out you will get data where the values start with those characters.
Even if you do filter them out there is nothing in what you posted that would prevent a user from inserting that data back into the table.
And, of course, there are characters that sort BETWEEN the lower and upper case alphabetics.
You need to determine what the allowable characters are in the PROD_DETAILS column and add code (e.g. check constraint or trigger) to make sure users can't enter data that includes those characters.