Solved

ORACLE 10g: Function - insert unique identifier using sequence

Posted on 2015-01-27
7
597 Views
Last Modified: 2015-01-28
Experts,

I have a function that truncates a table and inserts new data.  The data that is being inserted doesn't have a unique ID nor does it have a field that is unique in records.  Therefore, I want to create a unique id for each row, which has to be numbers only.  Any ideas on how to accomplish this?

Example:
Colum1 (ID)
1
2
3
4
5
etc

Thanks!
0
Comment
Question by:Maliki Hassani
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
7 Comments
 
LVL 74

Accepted Solution

by:
sdstuber earned 250 total points
ID: 40573928
if your inserted data is from a select statement, you can simply use ROWNUM

for example...

select rownum, t.* from all_tables t;


to create a sequence object is easy though

create sequence my_sequence;

insert into yourtable( id) values (my_sequence.nextval);'

or

select my_sequence.nextval,t.* from all_tables t;
0
 
LVL 23

Assisted Solution

by:David
David earned 250 total points
ID: 40573930
Create a sequence, initialize it, and use the built-in function to increment it.  INSERT into table VALUES (somesequence.nextval)  is the simplest, and doesn't require any trigger.
0
 
LVL 74

Expert Comment

by:sdstuber
ID: 40573943
also, if this is 12c,  you can associate a sequence with a column to create an "identity column" like you see in other databases.
0
Instantly Create Instructional Tutorials

Contextual Guidance at the moment of need helps your employees adopt to new software or processes instantly. Boost knowledge retention and employee engagement step-by-step with one easy solution.

 

Author Comment

by:Maliki Hassani
ID: 40573947
Great I will give this a try!
0
 

Author Comment

by:Maliki Hassani
ID: 40573959
I used rownum and that that worked.  Do I need to have a sequence added and applied or just use rownum?
0
 

Author Comment

by:Maliki Hassani
ID: 40574293
Let me rephrase that..  as for speed is it better to use sequence or row number?  Thanks
0
 
LVL 74

Expert Comment

by:sdstuber
ID: 40575069
the difference will be very minor, but rownum should probably be minorly more efficient since it never has to update the data dictionary but a sequence with a large cache value will minimize that.

Best way to verify is to simply run both on your system and test results.
0

Featured Post

[Webinar] Learn How Hackers Steal Your Credentials

Do You Know How Hackers Steal Your Credentials? Join us and Skyport Systems to learn how hackers steal your credentials and why Active Directory must be secure to stop them. Thursday, July 13, 2017 10:00 A.M. PDT

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

If you find yourself in this situation “I have used SELECT DISTINCT but I’m getting duplicates” then I'm sorry to say you are using the wrong SQL technique as it only does one thing which is: produces whole rows that are unique. If the results you a…
Using SQL Scripts we can save all the SQL queries as files that we use very frequently on our database later point of time. This is one of the feature present under SQL Workshop in Oracle Application Express.
This videos aims to give the viewer a basic demonstration of how a user can query current session information by using the SYS_CONTEXT function
This video shows how to recover a database from a user managed backup

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question