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Home -> Community -> Usenet -> c.d.o.server -> Re: getting NEXTVAL from User_sequences vs Dual
A copy of this was sent to markag_at_my-dejanews.com
(if that email address didn't require changing)
On Wed, 08 Jul 1998 18:01:27 GMT, you wrote:
>I'm curious as to why some of the existing code I'm working on retrieves the
>nextval for sequences through user_sequences instead of dual; example:
>
>"SELECT SEQ_CUST_ID.NextVal from USER_SEQUENCES"
>
>vs
>
>"SELECT SEQ_CUST_ID.NextVal from DUAL"
>
>I notice that when you retrieve from user_sequences, your nextval is
>incremented by the number of sequences within that schema times the increment
>value of the sequence, but when retrieved through DUAL, it is always the
>increment value. Is this because there is only one row in dual, and
>potentially many rows in user_sequences?
>
thats exactly right -- dual has one row, hence select seqname.nextval from dual
increments by 1. user_sequences has a row per sequence the current user owns
(or if called from a stored procedure the number of rows the owner of the
procedure can see in user_sequences) and will increment the sequence by that
amount.
they probably didn't understand dual -- I would change the query to be from dual instead of user_sequences...
>
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Thomas Kyte
tkyte_at_us.oracle.com
Oracle Government
Herndon VA
http://govt.us.oracle.com/ -- downloadable utilities
Anti-Anti Spam Msg: if you want an answer emailed to you, you have to make it easy to get email to you. Any bounced email will be treated the same way i treat SPAM-- I delete it. Received on Wed Jul 08 1998 - 14:28:11 CDT
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