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Author Topic: Pseudo columns in Oracle?  (Read 1231 times)
Sipra
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« on: June 20, 2007, 05:32:16 pm »
Hi friends,

Recently I attended an interview in which they have asked about pseudo columns.

They questioned me as follows:

What are pseudo columns in Oracle?

Can anybody give the perfect reply....? Please...
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Sipra
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« Reply #1 on: June 25, 2007, 12:16:11 pm »
The Pseudo Colums are  -
  • ROWID
  • ROWNUM
  • CURRVAL
  • NEXTVAL
  • LEVEL etc..,

One can select from Pseudo columns, but you can't insert, update or delete their values.
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Raj2007
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« Reply #2 on: July 02, 2007, 08:56:19 pm »
Update -

A Pseudocolumn behaves like a table column, but is not actually stored in the table.

As Whoever said,
You can select from the Pseudocolumns but you can't insert or update or delete their values.
« Last Edit: July 03, 2007, 10:31:23 am by Sipra » Logged
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« Reply #3 on: July 03, 2007, 10:48:29 am »
Here is a partial list of pseudo-columns in Oracle and their Description.

USER -
This pseudo-column will always contain the Oracle username under which you are connected to the database.

SYSDATE -
This pseudo-column will contain the current date and time. This column is a standard Oracle DATE datatype. The value represents the current time on the server not the client.

UID -
UID is the Identification code of a User (number associated with a user).

ROWID -
Rowid is always returns unique number correspoding to the row.

SYSDATE -
This pseudo-column will return current date and time

ROWNUM -         
This pseudo-column will return sequence number assigned to retrieved rows
« Last Edit: July 03, 2007, 11:00:59 am by mOrpheuS » Logged
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