| lvr |
Posted: May 26, 2008 11:17:47 PM |
Total Post: 12
Joined: May, 2008
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1. Write the Sql query for creating database backup?
2. What is TABLE SPACE?
3. Types of backups ?
4. How to create a primary key with out creating an index? is it possible?
5. Does SQL*Plus contains pl/sql Engine?
6. What is the fastest way of accessing a row in a table?
plz give answer for these questions |
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 Murtuja |
| Posted: May 27, 2008 12:42:37 AM |  |
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Total Post: 857
Joined: Jan, 2006
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Hi,
Read Oracle DBA books or try to read from online documents.
For que 6
Table access by ROWID
The rowid of a row specifies the datafile and data block containing the row and the location of the row in that block. Locating a row by specifying its rowid is the fastest way to retrieve a single row, because the exact location of the row in the database is specified.
To access a table by rowid, Oracle first obtains the rowids of the selected rows, either from the statement's WHERE clause or through an index scan of one or more of the table's indexes. Oracle then locates each selected row in the table based on its rowid.
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| Shoikat |
| Posted: May 27, 2008 12:45:52 AM | |
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Total Post: 1
Joined: May, 2008
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What is Table Space ?
An oracle database consists of two or more table spaces, and each table space consists of two or more datafile.
The data block size is a table space attribute. The database always allocates and uses disk space in units of data block.
CREATE TABLESPACE HR_DATA DATAFILE 'D:\oracle\oradata\ora10\hr_data.dbf'
TYPES of BACKUP ?
Whole - A whole database backup includes all datafile and at least one control file.
Partial- Partial database backup includes zero or more table space
Full - A full backup includes all block of every datafile backed up in a whole or partial database backup
Incremental - A incremental backup makes a copy of all data blocks that have change since a previous backup
Consistent- also known as off line backup . performed when database not open.
inconsistent- this is online backup. performed when database is open and available to user.
Does SQL*Plus contains pl/sql Engine?
yes
How to create a primary key with out creating an index? is it possible?
No it is not possible. primary creates an index implicitly.
plz someone ans question no. 1 and 6 and also some one plz verify my ans.
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| lvr |
| Posted: May 27, 2008 01:26:10 AM | |
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Total Post: 12
Joined: May, 2008
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hi Murtuja,
Thanks for ur guidance. but these questions were asked in my interview. i am not good in dba and dont want elaborate explanation. just give some valuable points .
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| Murtuja |
| Posted: May 27, 2008 01:32:06 AM | |
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Total Post: 857
Joined: Jan, 2006
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Hi LVR,
Are you working as DBA? Please tell me about your role.
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| lvr |
| Posted: May 27, 2008 02:02:42 AM | |
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Total Post: 12
Joined: May, 2008
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no i am working in java, j2ee..
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| Murtuja |
| Posted: May 27, 2008 08:33:52 AM | |
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Total Post: 857
Joined: Jan, 2006
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Hi,
As a Java developer you need to prepare about sql and pl/sql questions only.
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| Geetha |
| Posted: May 30, 2008 07:35:59 AM | |
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Total Post: 21
Joined: Mar, 2008
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Hi Murtuja,
I agree your answer for 6th question. I've few questions here. When I was using the below query, it took few minutes of time for its output.
select * from emp where rowid between 1 and 10;
Couldn't guess what the problm would be. Is this related to the number of records found in the database??? If not, could you please explain me the reason why the delay has happened???
Thanks,
Geetha
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| Gitesh |
| Posted: May 30, 2008 08:11:23 AM | |
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Total Post: 322
Joined: May, 2005
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There is no rowid available like 1 and 10. Due to this it is fetching full table scan for checking this.
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| Geetha |
| Posted: May 30, 2008 09:53:48 AM | |
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Total Post: 21
Joined: Mar, 2008
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Hi all...
I'm very sorry that instead of rownum, I mentioned as rowid...
The query is,
select * from emp where rownum between 1 and 10;
Could you plz suggest me???
Thanks,
Geetha
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