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Home -> Community -> Mailing Lists -> Oracle-L -> RE: db file sequential read [WAS:wait event puzzler]
>From the Oracle SQL reference:
The following rules apply when naming schema objects:
1. Names must be from 1 to 30 bytes long with these exceptions:
n Names of databases are limited to 8 bytes.
n Names of database links can be as long as 128 bytes.
2. Names cannot contain quotation marks.
3. Names are not case sensitive.
4. A name must begin with an alphabetic character from your database character
set unless surrounded by double quotation marks.
5. Names can contain only alphanumeric characters from your database character
set and the underscore (_), dollar sign ($), and pound sign (#). Oracle
strongly
discourages you from using $ and #. Names of database links can also contain
periods (.) and "at" signs (@).
Yes these limits are somewhat supported by the RDBMS dictionary tables, but by internal buffers as well. Violating them as is being suggested can and will cause a memory error within the kernel that will cause an ORA-00600 and termination of the instance. Recovery may or may not be possible. OTS will only support you IF you rebuild the instance with the standard scripts provided. BTDT with an friend who worked elsewhere in the past. He had inherited the database (7.3.4) from a duhveloper who did not believe in limits and was at best a loose cannon. The database was unrecoverable and had to be trashed, along with a several years worth of data. Believe it or not, but it was the upgrade to 7.3.4 from 7.3.0 that caused the problem. OH BTW, did I mention they did not believe in backups!!
Dick Goulet
Senior Oracle DBA
Oracle Certified 8i DBA
-----Original Message-----
Sent: Thursday, June 12, 2003 10:44 AM
To: Multiple recipients of list ORACLE-L
DON'T DO IT !!!!! Ur not supposed to Update Data Dictionaly Tables Directly ...
Oracle has A Limit of 30 Chrs and is Hardcoded.. So ReName your Columns within 30 Chrs...
DON'T DO IT !!!!!
Best Regards,
Ganesh R
DID : +65-6215-8413
HP : +65-9067-8474
-----Original Message-----
Bhaskar Viswanathan
Sent: Thursday, June 12, 2003 9:20 PM
To: Multiple recipients of list ORACLE-L
Hi Senthil,
One thing I can see is that this object col is not a user-defined table. Probably a system table.
I tried "alter table col modify cname varchar2(60)"
*
ERROR at line 1:
ORA-00942: table or view does not exist
But the object exists as I am able to do a select on it.
Please send me the procedure. I will try it out!
baski
-----Original Message-----
Sent: Thursday, June 12, 2003 5:05 PM
To: Multiple recipients of list ORACLE-L
Dear Bhaskar,
You can modify col$.NAME to varchar2(60) and try.
If this fails, I'll give a procedure you can use that to change it to whatever size you want.
Senthil Kumar
Sr Oracle DBA
Summitworks Technologies Pvt Ltd
-----Original Message-----
Bhaskar Viswanathan
Sent: Thursday, June 12, 2003 4:00 PM
To: Multiple recipients of list ORACLE-L
hi,
We use Oracle 8 DB.
I am not a Oracle technical guy. So lemme try explaining the problem.
We need to create tables with columns, whose names(column-names) are more than 30 characters long. This is being restricted because, all columns of all tables have entries in a table called 'col'. Thit table is defined as:
SQL> desc col
Name Null? Type ----------------------------------------- -------- ---------------------------- TNAME NOT NULL VARCHAR2(30) COLNO NOT NULL NUMBER CNAME NOT NULL VARCHAR2(30) COLTYPE VARCHAR2(106) WIDTH NOT NULL NUMBER SCALE NUMBER PRECISION NUMBER NULLS VARCHAR2(19) DEFAULTVAL LONG CHARACTER_SET_NAME VARCHAR2(44)SQL> since CNAME is defined as VARCHAR2(30), we are forced to retrict column names to a max of 30 characters long.
For eg. create table T1(xxxxxxxxxxxxxxxxxxxxxxxxxxxxx31 varchar2(50));
The above statement will be rejected with the error:
*
However, the statement "create table T1(xxxxxxxxxxxxxxxxxxxxxxxxxxxx30varchar2(50))" Succeeds in creating the table;
I guess this table col is created by the system itself. how can we change this size So that the 30 character restriction in column names can be avoided???
baski
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-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Bhaskar Viswanathan INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Senthil Kumar D INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). **************************Disclaimer************************************ Information contained in this E-MAIL being proprietary to Wipro Limited is 'privileged' and 'confidential' and intended for use only by the individual or entity to which it is addressed. You are notified that any use, copying or dissemination of the information contained in the E-MAIL in any manner whatsoever is strictly prohibited. ************************************************************************ *** -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Bhaskar Viswanathan INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Ganesh Raja INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Goulet, Dick INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Thu Jun 12 2003 - 09:46:32 CDT
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