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Composite Primary Key
WHat is Composite Primary Key?
hemant.agarwal03
- Mar 27th, 2008
Composite primary key used for multiple fields joined together to identify a records in a table. We can use maximum 16 columns for a composite primary key.
ddanda
- Mar 24th, 2008
when 2 attributes of the table form a primary key .such a key is known as composite primary key.
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Get fieldnames from Empty Table
How to get field names from empty table by using SELECT statement;
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Determine Number of Blocks Corrupted
You have a database. You have a datafile and some blocks are corrupted in the datafile. What statement will you issue to know how many blocks are corrupted?
kunal1017
- Apr 1st, 2008
you can use the DBVERIFY utility to check the corruption in datafiles so that you can now number of blocks corrupted.Here is the procedure :On o/s prompt login as oracle user : $ dbv file= &...
hemant.agarwal03
- Mar 12th, 2008
You can check the "V_$DATABASE_BLOCK_CORRUPTION" view to determine the corrupted blocks.
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Flash Back Query
What is a flash back query? This feature is also available in 9i. whats the difference between 9i and 10g (related to flash back query).
hemant.agarwal03
- Mar 12th, 2008
Oracle 10g offers significant enhancements that help insure the high availability of any Oracle database, as well as improvements in the database disaster recovery arena. This paper explores one of th...
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DBMS_meta_data Parameter
DBMS_meta_data. This parameter is very usefull. What you infer from this parameter. What info you will find in that. explain in detail.
hemant.agarwal03
- Mar 12th, 2008
To find the structure of a external table we used this package.syntax is below:SELECT DBMS_METADATA.GET_DDL ('TABLE','<Table Name in CAPS>')||';' FROM DUAL
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Datafile Size
What is your datafile size? How long it can go? What is the max limit to which you can extend?
hemant.agarwal03
- Mar 18th, 2008
v$datafile data dictionary view will tell us the size of a datafile.to check the number of datafile you can check db_files init parameter. you can also alter this parameter but it will reflect after restartthe database.you can also resize the datafile size.
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Compression Parameter
You have a database of 2GB. Can you convert the database to 1GB. Which compression parameter will you use?
hemant.agarwal03
- Mar 18th, 2008
COMPRESSION =(METADATA_ONLY | NONE) - This parameter applies from Oracle 10.2. It specifies whether to compress metadata before writing to the dump file set. Compression reduces the amount of disk spa...
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how to execute a sql*plus script from pl/sql block.
my script contains sql plus set commands. how to execute that script in a pl/sql block i.e. either anonymous ,procedure or function or trigger
hemant.agarwal03
- Mar 17th, 2008
First you need to save your file in .sql format, suppose you create set.sql and saved it on c: drive then follow below command.SQL> @C:SET.SQL and press ENTERyour script has been executed. :-)
Susil Kumar
- Feb 20th, 2008
Let me reframe the question as follows: How to execute pl/sql block in sql*plus environment?If I am on the right path, I'll be able to give th...
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Time taken by a query
What is the command to print the time taken by a query
hemant.agarwal03
- Feb 13th, 2008
you need to use set operetor TO GET THE TIME..LIKE THIS..SQL> SELECT SYSDATE FROM DUAL;SYSDATE---------13-FEB-08SQL> SET TIMING ONSQL> SELECT SYSDATE FROM DUAL;SYSDATE---------13-FEB-08Elapsed: 00:00:00.00now it will show time..
karunakaradepu
- Jan 29th, 2008
If UR Q is How TO PRINT A TIME: SELECT TO_CHAR(SYSDATE,'HH:MI:SS') FROM DUAL;
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If you 100 table spaces so how to find which table space is growing and which one is volatile?
narendra05
- Oct 2nd, 2009
In 10g the AWR repository keeps track of data for 60 days by default and can store the information of tablespace growth for this period.Alternativey you can set the threshold in entreprise manager for a tablespace to respective which can trigger email alert if configered.
hemant.agarwal03
- Mar 17th, 2008
Select sum(bytes),TABLESPACE_NAME from dba_segments group by TABLESPACE_NAMEorder by sum(bytes) desc/
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How do you create a primary key to existing table with duplicate records?
hemant.agarwal03
- Mar 17th, 2008
Alter table add constraint primary key ()DEFERRABLE initially immediate enable novalidate
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what is the use and advantage of procedure in datastage?
hemant.agarwal03
- Nov 13th, 2009
If we have a complex business logic and we may need to create mutiple jobs to achive that , then we use procedure in data stage which provide us final output in a single job. It is faster then normal SQL statement also.
Him121
- Jun 22nd, 2007
To trigger Database operations at before or after DB stage access.
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How can we order the column of day (mon to sun)such that monday comes first then tues and so no.Suppose we have retrieved day out of hiredate column
katgeektalk
- Aug 26th, 2010
Select hiredate, to_char(hiredate, 'Day') "DAY OF THE WEEK"from scott.emporder by to_char(hiredate-1, 'D')
dj_dj_dj
- Mar 22nd, 2010
Select to_char(hire_date, 'day')from table_nameorder by to_char(hire_date -1 ,'day');RegardsDharmendra Jaiswal
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What happens if i kill a mandatory background processes?
krish_makkena
- Aug 4th, 2010
If we kill the mandatory background processes the db should be shutdown i.e, instance is terminated.
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Command to show SQL commands from buffer
Which command displays the SQL command in the SQL buffer, and then executes it?
sandeep.katta
- Feb 3rd, 2011
RUN Command...... Check by following exampleSQL> select sysdate from dual;SYSDATE---------03-FEB-11SQL> run 1* select sysdate from dualSYSDATE---------03-FEB-11
hemant.agarwal03
- Mar 17th, 2008
LIST and L is correct but you can also type "ED" also on sqlplus window and enter, it will open a notepad window for you to edit (if you required) otherwise you can press ALT + F4 and ENTER key.
