AskTom - Hot Questions
Pipelined PARALLEL_ENABLE Table Function
Hi,
I am new here. This is my 1st question (actually I posted the same question today in the morning, but somehow removed I think, as I could not find it out. So, posting again).
When we create table partitions by range, we mention the range li...
Select statement sort without order by clause
Tom,
I am looking in the documentation where it states oracle doesn't guarantee the order of a select statement without an order by clause. I'm having trouble finding in to prove it to the higher ups. I know its a shot in the dark but do you know of...
Partitioning scheme
Our setup:
It's a packaged software which uses Oracle 11g in the data layer. Primarily we have three data tables
1. data_fact (Holds granular data)
2. data_hour_fact (Holds...
Using dbms_application_info using shared server mode and app server connection pool
Hi Tom
Many times you have mentioned that in shared server mode it is virtually impossible to use trace information. Well we have a 3rd party application server which implements connection pooling and uses JDBC to connect to our 11g Oracle databas...
Compare selected columns of two tables
Hi Tom
We have tables in two different databases and we would like to compare them using DBMS_COMPARISION package. The tables have standard WHO columns(creation_date,update_date,user) and this value will be different for the two tables. I know we...
Confused about the MAX size of varchar2
Hi Tom!
I've only worked with MS SQL Server in the past and only recently started with Oracle and must admit your knowledge/advice on this site always gets me past a problem.
I have something I want to ask though, not a problem, more a misunde...
Impart human knowledge to the optimizer?
Hi Tom ? long time lurker, first time submitter.
Running 11.2.0.3 on HP-UX ia64 B.11.31
This question may seem a bit off the wall on the surface ? in fact I?m struggling to find the find the right way to ask it, but here goes anyways?..
I?m ...
Flash back and data consistency
Hi Tom,
I was just thinking about recovery scenarios
Lets say I have a table called STOCK which contains products with a column to indicate how many I have on hand lets say the value of stock on hand is 1
An order gets processed that reduce...
forecast view
Hello Tom,
First the test data statements:
<code>create table temp
(
pk number,
obj varchar2(30),
due date,
freq number,
perioduom varchar2(10)
);
insert into temp values (1, 'obj1', to_date('25-02-2013','DD-MM-YYYY'), '1', 'Y');
inser...
11g compression
Hi Tom - We recently upgraded a database from 10g to 11g. When we did the upgrade, we brought over 3 months worth of data from the old database and started using the new database. When we initially started, the size of the database was 40gb. But sinc...
append vs Append_Values
Hi Tom,
We upgraded an application from Oracle 9i that used Append hint while inserting data into table for Direct-Path Inserts.
While going through Oracle 11g documentation I came to know that Append will not work if Valus clause is used and A...
Instance Recovery: How It works
Dear Sir,
May be subject line is not much attractive, I am very much confused about how actually recovery in Oracle work, more books,articals I read, more I confussed.
Please help me to find out "How actually recovery process in oracle works ?"
H...
Real World Performance Day Unique Index case study
Hi Tom,
I recently attended the Real World Performance session that Andrew and yourself ran in Perth, Australia.
There was one particular case study that you mentioned that I cannot remember all the details of. I was wondering if you'd be kind...
Optimizing Query
Hi,
I am looking for some advice on how to optimize my query. Here is my situation
I have the following table - STUDENTRESULTS
<code>
CREATE TABLE STUDENTRESULTS
(
SCHOOL_ID VARCHAR2(10 BYTE) NOT NULL
, STUDENT_ID VARCHAR2(10 BYTE) NO...
Database without Primary and foreign key
Hi Tom,
In our company we have a database without any primary and foreign keys.
For uniqueness they use unique and not null constraints in both dev and test environment and have delivered the same to all clients.
Example:
Table Tcoy:
Uniq...
REGEXP_REPLACE or Simple functions
Hi Tom,
I need to replace a word from a String with null from a text field with the following rules.
I am trying to frame the rule:
So the rule is replace the word TEST with null but if the word TEST is towards the end of the string al...
explicit Foreign Key constraints in DW
Hi Tom,
In all the 3 Data Warehouse projects that I had worked on we never created any Foreign key constraints in the fact tables explicitly. When I asked for the reason the standard answer that I get is "It will impact the performance and N...
Querying a remote pipelined function
Thanks Tom for your service to the Oracle community.
I usually find solutions to 99% of my questions on your site. But this is among the 1% that I couldn't find any solution anywhere.
I have two database servers DB_A and DB_B.
From DB_A I need t...

