Counting rows for db tables with 500 million+ entries

Hi
SE16 transaction timesout in foreground when showing number of entries for db tables with 500million+ entries. In background this takes too long.
I am writing a custom report to get number of records of a table and using OPEN CURSOR concept to determine number of records.
Is there any other efficient way to read number of records from such huge tables.
        OPEN CURSOR l_cursor FOR
        SELECT COUNT(*)
           FROM (u_str_param-p_tabn) WHERE (l_tab_cond). " u_str_param-p_tabn is the table name in input and l_tab_cond is a
          DO.                                                                              " dynamic where condition
            FETCH NEXT CURSOR l_cursor INTO l_new_count.
           PACKAGE SIZE p_pack.
            IF sy-subrc NE 0.
              EXIT.
            ELSE.
              l_tot_cnt = l_tot_cnt + l_new_count. " l_tot_cnt will contain number of records at end of loops
              CLEAR l_new_count.
            ENDIF.
          ENDDO.
          CLOSE CURSOR l_cursor.

Hello,
For sure it is a huge number of entries!!!
Is any key-fields?
Use a variable to keep a counter of the key-fields , for example row_table and also a low and high variable .
Try to use a do-loop and in this loop use:
do .
low_row = row_table.
low_high = row_table + 200.000.:increse the select every 200.000 entries
Do "select statement into table" based on the key-fields
For example : if the key-field is the docnr,
Do a "select into table itab where docnr >low_row
and docnr < low_high"
Count the lines of itab and keep them in a variable.
free the itab.
enddo
Good luck.
Antonis

Similar Messages

How much time it take to rebuild an index for a table with 20 millions rows

Hi all,
i need to rebuild the index of a table containing 20 000 000 row (i don't know why the other people working on this didn't think of rebuilding the index regularly, because i asked and apparently it has never been done :cry: :cry:) i am not a sql developper nor a DBA so i can't mesure how long it take to rebuild the index, does any one have an idea (aproximativly of course :aie:), the other question is there any formula to use in order to calculate how often to rebuild the indexes (i can for example retieve how much rows are delated or inserted daily ...)
Thanks again
Taha

taha wrote:
:aie: that's why i am asking because i don't know (and to be sure which solution is best)
so the table is like this (the columns) :
45 varchar2, 5 timestamp, 30 Number no LOB columns, (15 indexes : 5 unique indexes and that those indexes uses at a maximum 4 columns)15 indexes - 100,000 deletes: this could mean 1,500,000 block visits to maintain index leaf blocks as the table rows are deleted. If you're unlucky this could turn into 1,500,000 physical block read requests; if you're lucky, or the system is well engineered this could be virtually no physical I/O. The difference in time could be huge. At any rate it is likely to be 1,500,000 redo entries at 250 - 300 bytes per entry for a total of about 400MB of redo (so how large are your redo logs and how many log switches are you going to cause).
yes the tables is used by an application so (update, insert ) can take place at any time
for the deletion , there is the batch which does a mass delete on the table ( 4 or 5 time each day)
You haven't answered the question - how long does it take to do a sample batch delete.
If you can enable SQL tracing, or take a before/after snapshot of v$sesstat or v$session_event for the session as it does the delete then you can get some idea of where the time is going - for all you know it might be spending most of its time waiting for a lock to do away.
>
"How many leaf blocks are currently allocated to the index(es) ?" how can i answer to this question ? may be if i check the all_objects table ?
If you keep your statistics up to date then dba_indexes is a good place, cross-checked with dba_segments, and you can use the dbms_space package for more detail. I have a code sample on my blog which allows you to compare the current size of your indexes with the size they would be if rebuilt at some specific percentage: http://jonathanlewis.wordpress.com/index-sizing/ (It's such good code that Oracle Corp. has copied it into MOS note 989186.1)
Regards
Jonathan Lewis

Count rows from multiple tables using SQL only

Hi, I know this has probably been answered before, but I couldn't find the answer anywhere. Please help.
I'd like count(*) [rows] for all tables in database using SQL only - no PL/SQL
The result should be something like:
Table RowCount
DBA_TABLES 1000
DBA_USERS 50
etc.
Thanks!

offcource write this script:
create or replace procedure count_tables (ip_schema VARCHAR2)
is
lv_owner VARCHAR2(100);
lv_table_name VARCHAR2(100);
lv_sql_statement VARCHAR2(2000);
lv_count_table NUMBER;
CURSOR c1 IS
SELECT owner, table_name
FROM all_tables
WHERE owner = ip_schema
ORDER BY table_name;
begin
dbms_output.put_line ('+--------------------------------------------------------------------+');
dbms_output.put_line ('¦ | | ¦');
dbms_output.put_line ('¦ Schema Name | Table Name | Number of Rows ¦');
dbms_output.put_line ('¦ | | ¦');
dbms_output.put_line ('¦------------------------------------------------------------------¦');
OPEN c1;
LOOP
FETCH c1 INTO lv_owner , lv_table_name;
EXIT WHEN c1%NOTFOUND;
lv_sql_statement := 'SELECT count(*) FROM ' || lv_owner || '.' || lv_table_name;
EXECUTE IMMEDIATE lv_sql_statement INTO lv_count_table;
IF lv_count_table > 0 THEN
dbms_output.put_line ('| '||rpad(lv_owner, 14, ' ')||'| '|| rpad(lv_table_name, 32, ' ')||'| '|| rpad(lv_count_table, 16, ' ')||' |');
-- dbms_output.put_line ('|---------------|---------------------------------|------------------|');
END IF;
END LOOP;
CLOSE c1;
dbms_output.put_line ('+--------------------------------------------------------------------+');
exception
WHEN OTHERS THEN
dbms_output.put_line ('owner: '||lv_owner||' - table: '||lv_table_name||' - '||sqlerrm);
end count_tables;
set serveroutput on size 1000000
exec count_tables
drop procedure count_tables;

Issue in adding not null constraint on 250 G table with 50 million rows.

Guys,
I need to add not null constraint on 2 column of a table with 50 million rows and ~250 GB in size, These 2 columns are newly added and I have also update the value for each of these columns to not null for each row.
After that I am adding not null constraint on these 2 columns this is taking 1 hour to complete, Is there any way to speed up this, I don't want to use ENABLE NOVALIDATE option or rather I can't use that option.

user445775 wrote:
Guys,
I need to add not null constraint on 2 column of a table with 50 million rows and ~250 GB in size, These 2 columns are newly added and I have also update the value for each of these columns to not null for each row.
After that I am adding not null constraint on these 2 columns this is taking 1 hour to complete, Is there any way to speed up this, I don't want to use ENABLE NOVALIDATE option or rather I can't use that option.And what's wrong with it taking an hour? Presumably, this is a one time operation, and it doesn't really interfere with anything else.

What is the problem with native dynamic sql when counting rows in all table

what is the problem with native dynamic sql when counting rows in all table?Giving an error "table or view does not exist". Thanks.
DECLARE
v_sql_string varchar2(1000);
v_no_of_rows number;
BEGIN
for i in ( select table_name from all_tables )
loop
v_sql_string := ' select count(1) from ' || i.table_name;
dbms_output.put_line( v_sql_string );
--execute immediate v_sql_string into v_no_of_rows;
end loop;
END;

Usually your problem can be described with 'Who cares'. I mean, for what reason do you do this? I doubt that there's a business need to get 100 % accurate answers for this. Normally such things are used to get a picture about the growth of data.
Personally I would prefer to have up-to-date statistics for all tables and just query the number of rows from there. Sufficient for me in < 99 % of all cases.
Just my $ .02...

How to get count of rows for a table?

Hi,
How to get count of rows for a table and secondly, how can i have access to a particular cell in a table?
Regards,
Devashish

Hi Devashish,
WdContext.node<Your_node_name>().size() will give you the no: of rows.
This should be the node that is bound to the table's datasource property.
WdContext.node<Your_node_name>().get<node_name>ElementAt(index_value); will select the row at that particular index.
You can access an attribute of a particular row as
WdContext.node<Your_node_name>().get<node_name>ElementAt(index_value).get<attribute_name>();
Hope this helps,
Best Regards,
Nibu.
Message was edited by: Nibu Wilson

Count rows from several tables

hello,
im trying to count row from multiple tables
for example i need the select statement to produce the following
table_name count
table1 5
table2 6
table3 3
i came up with the following script but it counts the number of tables i have
select object_name, (select count(*) from user_tables where table_name = object_name) from all_objects
where object_type = 'TABLE'

Manik wrote:
May be possible:
Check this:
SELECT table_name,
TO_NUMBER (
EXTRACTVALUE (
xmltype (
DBMS_XMLGEN.getxml ('select count(*) c from ' || table_name)),
'/ROWSET/ROW/C'))
COUNT
FROM (select * from all_tables where table_name in ('TABLE1','TABLE2'))
WHERE owner = 'SCOTT';Cheers,
Manik.Awesome Manik... Just too good. Thanks.
I wish i could have given you the 'Correct' points. ;-)
Can you please explain the logic in brief? Will be helpful for everybody to understand...

Creating view to get first row for each table !!

I am having tables(more than 10) which are related using foreign key and primary key relationship.
Example:
Table1:
T1Prim T1Col1 T1Col2
Table2
T2For T2Prim T2Col1 T2Col2 T2Col3
(here T2For will have value same as T1Prim and in my design it has same column name i.e. T1Prim)
Table3
T3For T3Prim T3Col1 T3Col2 T3Col3
(here T3For will have value same as T2Prim)
and so on.
The data in the tables is like For table1 there will be one record, for table2 there will be one record and for table 3 there are more than one records.
Can i view either the first record for each of them or all records from each of them by writing the following view.
I have written a view like this:
Create or replace view test (T1Prim,T1Col1, T1Col2,T2Prim,T2Col1 T2Col2, T2Col3, T3Prim,T3Col1, T3Col2, T3Col3)
As
Select
Table1.T1Prim,
Table1.T1Col1,
Table1.T1Col2,
Table2.T2Prim,
Table2.T2Col1,
Table2.T2Col2,
Table2.T2Col3,
Table3.T3Prim,
Table3.T3Col1,
Table3.T3Col2,
Table3.T3Col3
From
Table1,
Table2,
Table3
where
Table1.Prim = Table2.For
and Table2.Prim = Table3.For
When i ran the select statement on the view I am not getting any data. Whereas there is data when select is ran on individual table.
Can someone please tell me where i am goofing.
Thanks in the anticipation that i will get some hint to solve this.
Eagerly waiting for reply.
Thanks !!

I mean use a collection :
Collection Methods
A collection method is a built-in function or procedure that operates on collections and is called using dot notation. The methods EXISTS, COUNT, LIMIT, FIRST, LAST, PRIOR, NEXT, EXTEND, TRIM, and DELETE help generalize code, make collections easier to use, and make your applications easier to maintain.
EXISTS, COUNT, LIMIT, FIRST, LAST, PRIOR, and NEXT are functions, which appear as part of an expression. EXTEND, TRIM, and DELETE are procedures, which appear as a statement. EXISTS, PRIOR, NEXT, TRIM, EXTEND, and DELETE take integer parameters. EXISTS, PRIOR, NEXT, and DELETE can also take VARCHAR2 parameters for associative arrays with string keys. EXTEND and TRIM cannot be used with index-by tables.
For more information, see "Using Collection Methods".
Syntax
Text description of the illustration collection_method_call.gif
Keyword and Parameter Description
collection_name
This identifies an index-by table, nested table, or varray previously declared within the current scope.
COUNT
COUNT returns the number of elements that a collection currently contains, which is useful because the current size of a collection is not always known. You can use COUNT wherever an integer expression is allowed.
For varrays, COUNT always equals LAST. For nested tables, normally, COUNT equals LAST. But, if you delete elements from the middle of a nested table, COUNT is smaller than LAST.
DELETE
This procedure has three forms. DELETE removes all elements from a collection. DELETE(n) removes the nth element from an index-by table or nested table. If n is null, DELETE(n) does nothing. DELETE(m,n) removes all elements in the range m..n from an index-by table or nested table. If m is larger than n or if m or n is null, DELETE(m,n) does nothing.
EXISTS
EXISTS(n) returns TRUE if the nth element in a collection exists. Otherwise, EXISTS(n) returns FALSE. Mainly, you use EXISTS with DELETE to maintain sparse nested tables. You can also use EXISTS to avoid raising an exception when you reference a nonexistent element. When passed an out-of-range subscript, EXISTS returns FALSE instead of raising SUBSCRIPT_OUTSIDE_LIMIT.
EXTEND
This procedure has three forms. EXTEND appends one null element to a collection. EXTEND(n) appends n null elements to a collection. EXTEND(n,i) appends n copies of the ith element to a collection. EXTEND operates on the internal size of a collection. So, if EXTEND encounters deleted elements, it includes them in its tally. You cannot use EXTEND with index-by tables.
FIRST, LAST
FIRST and LAST return the first and last (smallest and largest) subscript values in a collection. The subscript values are usually integers, but can also be strings for associative arrays. If the collection is empty, FIRST and LAST return NULL. If the collection contains only one element, FIRST and LAST return the same subscript value.
For varrays, FIRST always returns 1 and LAST always equals COUNT. For nested tables, normally, LAST equals COUNT. But, if you delete elements from the middle of a nested table, LAST is larger than COUNT.
index
This is an expression that must yield (or convert implicitly to) an integer in most cases, or a string for an associative array declared with string keys.
LIMIT
For nested tables, which have no maximum size, LIMIT returns NULL. For varrays, LIMIT returns the maximum number of elements that a varray can contain (which you must specify in its type definition).
NEXT, PRIOR
PRIOR(n) returns the subscript that precedes index n in a collection. NEXT(n) returns the subscript that succeeds index n. If n has no predecessor, PRIOR(n) returns NULL. Likewise, if n has no successor, NEXT(n) returns NULL.
TRIM
This procedure has two forms. TRIM removes one element from the end of a collection. TRIM(n) removes n elements from the end of a collection. If n is greater than COUNT, TRIM(n) raises SUBSCRIPT_BEYOND_COUNT. You cannot use TRIM with index-by tables.
TRIM operates on the internal size of a collection. So, if TRIM encounters deleted elements, it includes them in its tally.
Usage Notes
You cannot use collection methods in a SQL statement. If you try, you get a compilation error.
Only EXISTS can be applied to atomically null collections. If you apply another method to such collections, PL/SQL raises COLLECTION_IS_NULL.
You can use PRIOR or NEXT to traverse collections indexed by any series of subscripts. For example, you can use PRIOR or NEXT to traverse a nested table from which some elements have been deleted.
EXTEND operates on the internal size of a collection, which includes deleted elements. You cannot use EXTEND to initialize an atomically null collection. Also, if you impose the NOT NULL constraint on a TABLE or VARRAY type, you cannot apply the first two forms of EXTEND to collections of that type.
If an element to be deleted does not exist, DELETE simply skips it; no exception is raised. Varrays are dense, so you cannot delete their individual elements.
PL/SQL keeps placeholders for deleted elements. So, you can replace a deleted element simply by assigning it a new value. However, PL/SQL does not keep placeholders for trimmed elements.
The amount of memory allocated to a nested table can increase or decrease dynamically. As you delete elements, memory is freed page by page. If you delete the entire table, all the memory is freed.
In general, do not depend on the interaction between TRIM and DELETE. It is better to treat nested tables like fixed-size arrays and use only DELETE, or to treat them like stacks and use only TRIM and EXTEND.
Within a subprogram, a collection parameter assumes the properties of the argument bound to it. So, you can apply methods FIRST, LAST, COUNT, and so on to such parameters. For varray parameters, the value of LIMIT is always derived from the parameter type definition, regardless of the parameter mode.
Examples
In the following example, you use NEXT to traverse a nested table from which some elements have been deleted:
i := courses.FIRST; -- get subscript of first element
WHILE i IS NOT NULL LOOP
-- do something with courses(i)
i := courses.NEXT(i); -- get subscript of next element
END LOOP;
In the following example, PL/SQL executes the assignment statement only if element i exists:
IF courses.EXISTS(i) THEN
courses(i) := new_course;
END IF;
The next example shows that you can use FIRST and LAST to specify the lower and upper bounds of a loop range provided each element in that range exists:
FOR i IN courses.FIRST..courses.LAST LOOP ...
In the following example, you delete elements 2 through 5 from a nested table:
courses.DELETE(2, 5);
In the final example, you use LIMIT to determine if you can add 20 more elements to varray projects:
IF (projects.COUNT + 20) < projects.LIMIT THEN
-- add 20 more elements
Related Topics
Collections, Functions, Procedures
http://download-west.oracle.com/docs/cd/B10501_01/appdev.920/a96624/13_elems7.htm#33054
Joel P�rez

I am trying to insert rows for alert_id 22 with diff abc_id and xyz_id

I am trying to insert rows for alert_id 22 with diff abc_id and xyz_id
these inserts will store in two tables that I have to join in the cursor.
I have written cursor without passing cursor parameters. but here i need to pass acb_id and xyz_id along with alert_id.
then if these are saticified with alert_id 22 then I want to stop the loop run, else i need to continue the loop. bcause the abc_id and xyz_id are diff for alert_id 22
This is the issue I am facing!
Please let me know if you have any idea. Let me know how to use cursor parameters here and in loop.
Sample proc like this::
Declare
main_cursor
another_cur
alert_cur
begin
need to check first abc_id,xyz_id is already exist with alert_id 22
if this set of records already exists then
exit from the loop
else
continue with
loop
here coming the insert statements with different condition getting from first two cursors.(this part is ok for me)
end loop
end if
Please write the logic if any idea on this.
-LRK

I want to stop if already alert_id is exist!

Row chaining in table with more than 255 columns

Hi,
I have a table with 1000 columns.
I saw the following citation: "Any table with more then 255 columns will have chained
rows (we break really wide tables up)."
If I insert a row populated with only the first 3 columns (the others are null), is a row chaining occurred?
I tried to insert a row described above and no row chaining occurred.
As I understand, a row chaining occurs in a table with 1000 columns only when the populated data increases
the block size OR when more than 255 columns are populated. Am I right?
Thanks
dyahav

user10952094 wrote:
Hi,
I have a table with 1000 columns.
I saw the following citation: "Any table with more then 255 columns will have chained
rows (we break really wide tables up)."
If I insert a row populated with only the first 3 columns (the others are null), is a row chaining occurred?
I tried to insert a row described above and no row chaining occurred.
As I understand, a row chaining occurs in a table with 1000 columns only when the populated data increases
the block size OR when more than 255 columns are populated. Am I right?
Thanks
dyahavYesterday, I stated this on the forum "Tables with more than 255 columns will always have chained rows." My statement needs clarification. It was based on the following:
http://download.oracle.com/docs/cd/B28359_01/server.111/b28318/schema.htm#i4383
"Oracle Database can only store 255 columns in a row piece. Thus, if you insert a row into a table that has 1000 columns, then the database creates 4 row pieces, typically chained over multiple blocks."
And this paraphrase from "Practical Oracle 8i":
V$SYSSTAT will show increasing values for CONTINUED ROW FETCH as table rows are read for tables containing more than 255 columns.
Related information may also be found here:
http://download.oracle.com/docs/cd/B10501_01/server.920/a96524/c11schem.htm
"When a table has more than 255 columns, rows that have data after the 255th column are likely to be chained within the same block. This is called intra-block chaining. A chained row's pieces are chained together using the rowids of the pieces. With intra-block chaining, users receive all the data in the same block. If the row fits in the block, users do not see an effect in I/O performance, because no extra I/O operation is required to retrieve the rest of the row."
http://download.oracle.com/docs/html/B14340_01/data.htm
"For a table with several columns, the key question to consider is the (average) row length, not the number of columns. Having more than 255 columns in a table built with a smaller block size typically results in intrablock chaining.
Oracle stores multiple row pieces in the same block, but the overhead to maintain the column information is minimal as long as all row pieces fit in a single data block. If the rows don't fit in a single data block, you may consider using a larger database block size (or use multiple block sizes in the same database). "
Why not a test case?
Create a test table named T4 with 1000 columns.
With the table created, insert 1,000 rows into the table, populating the first 257 columns each with a random 3 byte string which should result in an average row length of about 771 bytes.
SPOOL C:\TESTME.TXT
SELECT
SN.NAME,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
INSERT INTO T4 (
COL1,
COL2,
COL3,
COL255,
COL256,
COL257)
SELECT
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3)
FROM
DUAL
CONNECT BY
LEVEL<=1000;
SELECT
SN.NAME,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
SET AUTOTRACE TRACEONLY STATISTICS
SELECT
FROM
T4;
SET AUTOTRACE OFF
SELECT
SN.NAME,
SN.STATISTIC#,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
SPOOL OFFWhat are the results of the above?
Before the insert:
NAME                      VALUE
table fetch continue        166
After the insert:
NAME                      VALUE
table fetch continue        166
After the select:
NAME                 STATISTIC#      VALUE
table fetch continue        252        332 Another test, this time with an average row length of about 12 bytes:
DELETE FROM T4;
COMMIT;
SPOOL C:\TESTME2.TXT
SELECT
SN.NAME,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
INSERT INTO T4 (
COL1,
COL256,
COL257,
COL999)
SELECT
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3)
FROM
DUAL
CONNECT BY
LEVEL<=100000;
SELECT
SN.NAME,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
SET AUTOTRACE TRACEONLY STATISTICS
SELECT
FROM
T4;
SET AUTOTRACE OFF
SELECT
SN.NAME,
SN.STATISTIC#,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
SPOOL OFFWith 100,000 rows each containing about 12 bytes, what should the 'table fetch continued row' statistic show?
Before the insert:
NAME                      VALUE
table fetch continue        332
After the insert:
NAME                      VALUE
table fetch continue        332
After the select:
NAME                 STATISTIC#      VALUE
table fetch continue        252      33695The final test only inserts data into the first 4 columns:
DELETE FROM T4;
COMMIT;
SPOOL C:\TESTME3.TXT
SELECT
SN.NAME,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
INSERT INTO T4 (
COL1,
COL2,
COL3,
COL4)
SELECT
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3),
DBMS_RANDOM.STRING('A',3)
FROM
DUAL
CONNECT BY
LEVEL<=100000;
SELECT
SN.NAME,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
SET AUTOTRACE TRACEONLY STATISTICS
SELECT
FROM
T4;
SET AUTOTRACE OFF
SELECT
SN.NAME,
SN.STATISTIC#,
MS.VALUE
FROM
V$MYSTAT MS,
V$STATNAME SN
WHERE
SN.NAME = 'table fetch continued row'
AND SN.STATISTIC#=MS.STATISTIC#;
SPOOL OFFWhat should the 'table fetch continued row' show?
Before the insert:
NAME                      VALUE
table fetch continue      33695
After the insert:
NAME                      VALUE
table fetch continue      33695
After the select:
NAME                 STATISTIC#      VALUE
table fetch continue        252      33695 My statement "Tables with more than 255 columns will always have chained rows." needs to be clarified:
"Tables with more than 255 columns will always have chained rows +(row pieces)+ if a column beyond column 255 is used, but the 'table fetch continued row' statistic +may+ only increase in value if the remaining row pieces are found in a different block."
Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc.
Edited by: Charles Hooper on Aug 5, 2009 9:52 AM
Paraphrase misspelled the view name "V$SYSSTAT", corrected a couple minor typos, and changed "will" to "may" in the closing paragraph as this appears to be the behavior based on the test case.

How to limit rows for a table?

Hi,
does anyone knows a good way to limit the number of rows for a table?
thanks
aldo

You can limit the number of rows using a trigger. Below is quick and dirty example that has not been fully tested.
test@ORCL> create table rowlimit (col1 number);
Table created.
Elapsed: 00:00:00.34
test@ORCL> create or replace trigger limit_rows
2 before insert
3 on rowlimit
4 declare
5    v_count number;
6 begin
7     select count(*)
8     into v_count
9     from rowlimit;
10
11     if v_count >= 4 then
12       raise_application_error(-20000, 'Table can have no more then 4 rows');
13     end if;
14 end;
15 /
Trigger created.
Elapsed: 00:00:00.09
test@ORCL> insert into rowlimit values(1);
1 row created.
Elapsed: 00:00:00.03
test@ORCL> insert into rowlimit values(2);
1 row created.
Elapsed: 00:00:00.00
test@ORCL> insert into rowlimit values(3);
1 row created.
Elapsed: 00:00:00.00
test@ORCL> insert into rowlimit values(4);
1 row created.
Elapsed: 00:00:00.00
test@ORCL> insert into rowlimit values(5);
insert into rowlimit values(5)
ERROR at line 1:
ORA-20000: Table can have no more then 4 rows
ORA-06512: at "TEST.LIMIT_ROWS", line 9
ORA-04088: error during execution of trigger 'TEST.LIMIT_ROWS'
Elapsed: 00:00:00.04
test@ORCL> commit;
Commit complete.
Elapsed: 00:00:00.00
test@ORCL> select count(*) from rowlimit;
COUNT(*)
         4
Elapsed: 00:00:00.00
test@ORCL>

Multiple header rows for one table?

Using html it's possible to set up multiple table header rows for one table but with APEX Reports I don't see how to implement this. Any ideas?
I want to use the second header row to provide links to data for the column only (not a row). But I still want sortable columns so I want to maintain the default column header behavior too.
Thanks,
Linda

Mike,
I tried that and found that indeed the substitution string is working and shows in both debug regions I set up on each page I tested.
I have tried this on two kinds of pages. It works correctly on standard pages with PPR report regions.
It is not working correctly on a page based on Carl's tabbed regions with PPR reports. One click and the header disappears. This is the version I really want to get working.
I'd like to post something but have asked twice for a space on apex.oracle.com and have yet to receive even an email acknowledging my request.
Perhaps you can help me get a space?
My new problem on the tabbed page where my multiple headers are working is that when I click on a link in the header, it loads that page below the tab. But if I now click on the tab again, rather than return to the original tab page, I get error "ERR-1777: Page 4042 provided no page to branch to. Please report this error to your application administrator. " This happens on both the tabbed regions pages and on the standard tabbed pages. I guess I need to provide a differently formatted url? It is currently like this -
-----------------------"<th id="opt-details1" [a href="f?p=&APP_ID.:3001:&APP_SESSION.:::::"] View Details</a></th>" --------------[not really square brackets but I didn't know how to make this show in the forum with proper <> brackets ----------------------
Thanks again,
Linda
---sorry for the lack of white space. It seems to happen when I post on forums on Sunday nights - all white space is removed.

Error inserting a row into a table with identity column using cfgrid on change

I got an error on trying to insert a row into a table with identity column using cfgrid on change see below
also i would like to use cfstoreproc instead of cfquery but which argument i need to pass and how to use it usually i use stored procedure
update table (xxx,xxx,xxx)
values (uu,uuu,uu)
     My component

    <cffunction name="cfn_MediaType_Update" access="remote">
        <cfargument name="gridaction" type="string" required="yes">
        <cfargument name="gridrow" type="struct" required="yes">
        <cfargument name="gridchanged" type="struct" required="yes">
        
        <cfset var colname="">
        <cfset var value="">
        
        <cfswitch expression="#ARGUMENTS.gridaction#">
            
            <cfcase value="U">
                
                <cfset colname=StructKeyList(ARGUMENTS.gridchanged)>
                <cfset value=ARGUMENTS.gridchanged[colname]>
                
                <cfquery datasource="#application.dsn#">
                UPDATE SP.MediaType
                SET #colname# = '#value#'
                WHERE MediaTypeID = #ARGUMENTS.gridrow.MediaTypeID#
                </cfquery>
            </cfcase>
            
            <cfcase value="D">
                
                <cfquery datasource="#application.dsn#">
                update SP.MediaType
                set Deleted=1
                WHERE MediaTypeID = #ARGUMENTS.gridrow.MediaTypeID#
                </cfquery>
            </cfcase>
            <cfcase value="I">
                
                <cfset colname=StructKeyList(ARGUMENTS.gridchanged)>
                <cfset value=ARGUMENTS.gridchanged[colname]>
                
               <cfquery datasource="#application.dsn#">
                insert into SP.MediaType (#colname#)
                Values ('#value#')
                </cfquery>
            </cfcase>
        </cfswitch>
    </cffunction>
my table
mediatype:
mediatypeid primary key,identity
mediatypename
my code is
<cfform method="post" name="GridExampleForm">
        <cfgrid format="html" name="grid_Tables2" pagesize="3" selectmode="edit" width="800px"
        delete="yes"
        insert="yes"
            bind="cfc:sp3.testing.MediaType.cfn_MediaType_All
                                                            ({cfgridpage},{cfgridpagesize},{cfgridsortcolumn},{cfgridsortdirection})"
              onchange="cfc:sp3.testing.MediaType.cfn_MediaType_Update({cfgridaction},
                                            {cfgridrow},
                                            {cfgridchanged})">
            <cfgridcolumn name="MediaTypeID" header="ID" display="no"/>
            <cfgridcolumn name="MediaTypeName" header="Media Type" />
        </cfgrid>
</cfform>
on insert I get the following error message ajax logging error message
http: Error invoking xxxxxxx/MediaType.cfc : Element '' is undefined in a CFML structure referenced as part of an expression.
{"gridaction":"I","gridrow":{"MEDIATYPEID":"","MEDIATYPENAME":"uuuuuu","CFGRIDROWINDEX":4} ,"gridchanged":{}}
Thanks

Is this with the Travel database or another database?
If it's another database then make sure your columns
allow nulls. To check this in the Server Navigator, expand
your DataSource down to the column.
Select the column and view the Is Nullable property
in the Property Sheet
If still no luck, check out a tutorial, like Performing Inserts, ...
http://developers.sun.com/prodtech/javatools/jscreator/learning/tutorials/index.jsp
John

What index is suitable for a table with no unique columns and no primary key

alpha
beta
gamma
col1
col2
col3
100
1
-1
a
b
c
100
1
-2
d
e
f
101
1
-2
t
t
y
102
2
1
j
k
l
Sample data above and below is the dataype for each one of them
alpha datatype- string
beta datatype-integer
gamma datatype-integer
col1,col2,col3 are all string datatypes.
Note:columns are not unique and we would be using alpha,beta,gamma to uniquely identify a record .Now as you see my sample data this is in a table which doesnt have index .I would like to have a index created covering these columns (alpha,beta,gamma) .I
beleive that creating clustered index having covering columns will be better.
What would you recommend the index type should be here in this case.Say data volume is 1 milion records and we always use the alpha,beta,gamma columns when we filiter or query records
what index is suitable for a table with no unique columns and primary key?
col1
col2
col3
Mudassar

Many thanks for your explanation .
When I tried querying using the below query on my heap table the sql server suggested to create NON CLUSTERED INDEX INCLUDING columns ,[beta],[gamma] ,[col1]
,[col2] ,[col3]
SELECT [alpha]
,[beta]
,[gamma]
,[col1]
,[col2]
,[col3]
FROM [TEST].[dbo].[Test]
where [alpha]='10100'
My question is why it didn't suggest Clustered INDEX and chose NON clustered index ?
Mudassar

What is the maximum number of row for a table control in LabWindows/CVI ?

I use LabWindows CVI 8.5.1 (MMI first developped in version 6.0).
In one of our many MMI, a table control contains a list of aircraft parameters.
We can add as many parameters (row) as we want but over 40 000 we observe a crash of the LabWindows CVI runtime.
Our client want to inscrease the number of parameters (row) up to 200 000 !!!
So my questions are:
What is the real maximum number of row for the table control ?
Is this maximum number of row different on LabWindows 2010 version ?
Or is there an other solution ?
Thanks

Greetings,
Can you clarify what you mean by "crash"? Is there an error message thrown? Is it possible that you've consumed all of the available memory?
Please let me know.
Thanks, James Duvall
Product Support Engineer
National Instruments

Counting rows for db tables with 500 million+ entries

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