SQL - What is the difference between ROWNUM and ROWID

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What is the difference between ROWNUM and ROWID

Total Answers and Comments: 6

Last Update: February 26, 2008 Asked by: kamaldass

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March 04, 2006 05:47:23

rameshnaidu

RE: what is the difference between ROWNUM and ROWID

the ROWNUM is a number(like serial no) which is dynamically changes.but the ROWID does not change.Because it is having the unique address which is generated by the oracle

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March 25, 2006 04:38:29

dwhprofessional

Member Since: March 2006 Contribution: 6

RE: what is the difference between ROWNUM and ROWID

rownum is a pseudo column. It numbers the records in a result set. The first record that meets the where criteria in a select statement is given rownum 1 and every subsequent record meeting that same criteria increases rownum.

A rowid is a pseudo column (like versions_xid) that uniquely identifies a row within a table but not within a database. It is possible for two rows of two different tables stored in the same cluster to have the same rowid.

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May 17, 2006 10:44:27

nileshsingh

Member Since: May 2006 Contribution: 12

RE: what is the difference between ROWNUM and ROWID

rowid is a hexadecimal representation and

rownum is normal representation of rows uniquely.

SQL> select rowid rownum i from t1;

ROWID ROWNUM I
--------------------------------------------- -------------- ----------
AAAM6MAABAAAO8qAAA 1 1
AAAM6MAABAAAO8qAAB 2 2
AAAM6MAABAAAO8qAAC 3 3
AAAM6MAABAAAO8qAAD 4 4
AAAM6MAABAAAO8qAAE 5 5

SQL> select rowid rownum i from t1 where i in (1 2 4 5);

ROWID ROWNUM I
--------------------------------------------- -------------- ----------
AAAM6MAABAAAO8qAAA 1 1
AAAM6MAABAAAO8qAAB 2 2
AAAM6MAABAAAO8qAAD 3 4
AAAM6MAABAAAO8qAAE 4 5

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September 02, 2007 07:28:05

roniprasan

Member Since: September 2007 Contribution: 3

RE: what is the difference between ROWNUM and ROWID

Rowid is a psudo column and system generated id to a row which is a alphanumaric value. It contains 16 charecters. Rownum is a psudo column which is a sequential order of numbers given to the rows.

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February 06, 2008 23:16:33

g_sidhu

Member Since: August 2007 Contribution: 122

RE: What is the difference between ROWNUM and ROWID

Rowid: Hexadecimal string representing the unique address of a row in its table. This datatype is primarily for values returned by the ROWID pseudocolumn.

Rownum: For each row returned by a query the ROWNUM pseudocolumn returns a number indicating the order in which Oracle selects the row from a table or set of joined rows. The first row selected has a ROWNUM of 1 the second has 2 and so on. You can use ROWNUM to limit the number of rows returned by a query as in this example:

SELECT * FROM employees WHERE ROWNUM < 10;

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February 26, 2008 05:43:01

sampra

Member Since: February 2008 Contribution: 278

RE: What is the difference between ROWNUM and ROWID

the ROWNUM is a number(like serial no) which is dynamically changes.but the ROWID does not change.Because it is having the unique address which is generated by the oracle

Is this answer useful? Yes | No

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