1. To see current user name
Sql> show user;
2. Change SQL prompt name
SQL> set sqlprompt “Manimara > “
Manimara >
Manimara >
3. Switch to DOS prompt
SQL> host
4. How do I eliminate the duplicate rows ?
SQL> delete from table_name where rowid not in (select max(rowid)
from table group by duplicate_values_field_name);
or
SQL> delete duplicate_values_field_name dv from table_name ta where
rowid <(select min(rowid) from table_name tb where ta.dv=tb.dv);
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13. Display the number value in Words
SQL> select sal, (to_char(to_date(sal,'j'), 'jsp')) from emp;
14. Display Odd/ Even number of records
Odd number of records:
select * from emp where (rowid,1) in (select rowid, mod(rownum,2) from emp);
1
3
5
Even number of records:
select * from emp where (rowid,0) in (select rowid, mod(rownum,2) from emp)
2
4
6
15. Which date function returns number value?
months_between
16. Any three PL/SQL Exceptions?
Too_many_rows, No_Data_Found, Value_Error, Zero_Error, Others
17. What are PL/SQL Cursor Exceptions?
Cursor_Already_Open, Invalid_Cursor
18. Other way to replace query result null value with a text
SQL> Set NULL ‘N/A’ to reset SQL> Set NULL ‘’
19. What are the more common pseudo-columns?
SYSDATE, USER , UID, CURVAL, NEXTVAL, ROWID, ROWNUM
20. What is the output of SIGN function?
1 for positive value, 0 for Zero, -1 for Negative value.
21. What is the maximum number of triggers, can apply to a single table?
12 triggers.
21. How would you determine the time zone under which a database was operating?
select DBTIMEZONE from dual;
22. Explain the use of setting GLOBAL_NAMES equal to TRUE.
Setting GLOBAL_NAMES dictates how you might connect to a database. This
variable is either TRUE or FALSE and if it is set to TRUE it enforces database
links to have the same name as the remote database to which they are linking.
23. What command would you use to encrypt a PL/SQL application?
WRAP
24. Explain the difference between a FUNCTION, PROCEDURE and PACKAGE.
A function and procedure are the same in that they are intended to be a
collection of PL/SQL code that carries a single task. While a procedure does
not have to return any values to the calling application, a function will return
a single value. A package on the other hand is a collection of functions and
procedures that are grouped together based on their commonality to a
business function or application.
25. Explain the use of table functions.
Table functions are designed to return a set of rows through PL/SQL logic
but are intended to be used as a normal table or view in a SQL statement.
They are also used to pipeline information in an ETL process.
26. Name three advisory statistics you can collect.
Buffer Cache Advice, Segment Level Statistics, & Timed Statistics
27. Where in the Oracle directory tree structure are audit traces placed?
In unix $ORACLE_HOME/rdbms/audit, in Windows the event viewer
28. Explain materialized views and how they are used.
Materialized views are objects that are reduced sets of information that
have been summarized, grouped, or aggregated from base tables. They
are typically used in data warehouse or decision support systems.
29. When a user process fails, what background process cleans up after it?
PMON
30. What background process refreshes materialized views?
The Job Queue Processes.
31. How would you determine what sessions are connected and what resources they
are waiting for?
Use of V$SESSION and V$SESSION_WAIT
32. Describe what redo logs are.
Redo logs are logical and physical structures that are designed to hold all
the changes made to a database and are intended to aid in the recovery
of a database.
33. How would you force a log switch?
ALTER SYSTEM SWITCH LOGFILE;
34. Give two methods you could use to determine what DDL changes have been made.
You could use Logminer or Streams
35. What does coalescing a tablespace do?
Coalescing is only valid for dictionary-managed tablespaces and
de-fragments space by combining neighboring free extents into large
single extents.
36. What is the difference between a TEMPORARY tablespace and a PERMANENT
tablespace?
A temporary tablespace is used for temporary objects such as sort
structures while permanent tablespaces are used to store those
objects meant to be used as the true objects of the database.
37. Name a tablespace automatically created when you create a database.
The SYSTEM tablespace.
38. When creating a user, what permissions must you grant to allow them
to connect to the database?
Grant the CONNECT to the user.
39. How do you add a data file to a tablespace?
ALTER TABLESPACE
DATAFILE
40. How do you resize a data file?
ALTER DATABASE DATAFILE
41. What view would you use to look at the size of a data file?
DBA_DATA_FILES
42. What view would you use to determine free space in a tablespace?
DBA_FREE_SPACE
43. How would you determine who has added a row to a table?
Turn on fine grain auditing for the table.
44. How can you rebuild an index?
ALTER INDEX
45. Explain what partitioning is and what its benefit is.
Partitioning is a method of taking large tables and indexes and splitting them into
smaller, more manageable pieces.
46. You have just compiled a PL/SQL package but got errors, how would you view
the errors?
SHOW ERRORS
47. How can you gather statistics on a table?
The ANALYZE command.
48. How can you enable a trace for a session?
Use the DBMS_SESSION.SET_SQL_TRACE or
Use ALTER SESSION SET SQL_TRACE = TRUE;
49. What is the difference between the SQL*Loader and IMPORT utilities?
These two Oracle utilities are used for loading data into the database.
The difference is that the import utility relies on the data being
produced by another Oracle utility EXPORT while the SQL*Loader
utility allows data to be loaded that has been produced by other
utilities from different data sources just so long as it conforms to ASCII
formatted or delimited files.
50. Name two files used for network connection to a database.
TNSNAMES.ORA and SQLNET.ORA
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