Tuesday, August 2, 2011

More oracle DBA interview question and answer


What is the Maximum allowed length of Record group Column?
Record group column names cannot exceed 30 characters.
Which parameter can be used to set read level consistency across multiple queries?
Read only
What are the different types of Record Groups?
Query Record Groups
NonQuery Record Groups
State Record Groups
From which designation is it preferred to send the output to the printed? 
Previewer
What are difference between post database commit and post-form commit?
Post-form commit fires once during the post and commit transactions process, after the database commit occurs. The post-form-commit trigger fires after inserts, updates and deletes have been posted to the database but before the transactions have been finalized in the issuing the command. The post-database-commit trigger fires after oracle forms issues the commit to finalized transactions.
What are the different display styles of list items?
Pop_listText_listCombo box
Which of the above methods is the faster method?
performing the calculation in the query is faster.
With which function of summary item is the compute at options required?
percentage of total functions.
What are parameters?
Parameters provide a simple mechanism for defining and setting the valuesof inputs that are required by a form at startup. Form parameters are variables of type char,number,date that you define at design time.
What are the three types of user exits available ?
Oracle Precompiler exits, Oracle call interface, NonOracle user exits.
How many windows in a form can have console?
Only one window in a form can display the console, and you cannot change the console assignment at runtime.
What is an administrative (privileged) user? (for DBA )
Oracle DBAs and operators typically use administrative accounts to manage the database and database instance. An administrative account is a user that is granted SYSOPER or SYSDBA privileges. SYSDBA and SYSOPER allow access to a database instance even if it is not running. Control of these privileges is managed outside of the database via password files and special operating system groups. This password file is created with the orapwd utility.
What are the two repeating frame always associated with matrix object?
One down repeating frame below one across repeating frame.
What are the master-detail triggers?
On-Check_delete_masterOn_clear_detailsOn_populate_details
How does one connect to an administrative user? (for DBA )
If an administrative user belongs to the "dba" group on 
Unix, or the "ORA_DBA" (ORA_sid_DBA) group on NT, he/she can connect like this:
connect / as sysdba
No password is required. This is equivalent to the desupported "connect internal" method.
A password is required for "non-secure" administrative access. These passwords are stored in password files. Remote connections via Net8 are classified as non-secure. Look at this example:
connect sys/password as sysdba
How does one create a password file? (for DBA )
The Oracle Password File ($ORACLE_HOME/dbs/orapw or orapwSID) stores passwords for users with administrative privileges. One needs to create a password files before remote administrators (like OEM) will be allowed to connect.
Follow this procedure to create a new password file:
. Log in as the 
Oracle software owner
. Runcommand: orapwd file=$ORACLE_HOME/dbs/orapw$ORACLE_SID password=mypasswd
. Shutdown the database (SQLPLUS> SHUTDOWN IMMEDIATE)
. Edit the INIT.ORA file and ensure REMOTE_LOGIN_PASSWORDFILE=exclusive is set.
. Startup the database (SQLPLUS> STARTUP)
NOTE: The orapwd utility presents a 
security risk in that it receives a password from the command line. This password is visible in the process table of many systems. Administrators needs to be aware of this!
Is it possible to modify an external query in a report which contains it?
No.
Does a grouping done for objects in the layout editor affect the grouping done in the data model editor?
No.
How does one add users to a password file? (for DBA )
One can select from the SYS.V_$PWFILE_USERS view to see which users are listed in the password file. New users can be added to the password file by granting them SYSDBA or SYSOPER privileges, or by using the orapwd utility. GRANT SYSDBA TO scott;
If a break order is set on a column would it affect columns which are under the column?
No
Why are OPS$ accounts a security risk in a client/server environment? (for DBA)
If you allow people to log in with OPS$ accounts from Windows 
Workstations, you cannot be sure who they really are. With terminals, you can rely on operating system passwords, with Windows, you cannot.
If you set REMOTE_OS_AUTHENT=TRUE in your init.ora file, Oracle assumes that the remote OS has authenticated the user. If REMOTE_OS_AUTHENT is set to FALSE (recommended), remote users will be unable to connect without a password. IDENTIFIED EXTERNALLY will only be in effect from the local host. Also, if you are using "OPS$" as your prefix, you will be able to log on locally with or without a password, regardless of whether you have identified your ID with a password or defined it to be IDENTIFIED EXTERNALLY.
Do user parameters appear in the data modal editor in 2.5?
No
Can you pass data parameters to forms?
No
Is it possible to link two groups inside a cross products after the cross products group has been created?
no
What are the different modals of windows?
Modalless windows
Modal windows
What are modal windows?
Modal windows are usually used as dialogs, and have restricted functionality compared to modelless windows. On some platforms for example operators cannot resize, scroll or iconify a modal window.
What are the different default triggers created when Master Deletes Property is set to Non-isolated?
Master Deletes Property Resulting Triggers
----------------------------------------------------
Non-Isolated(the default) On-Check-Delete-Master
On-Clear-Details
On-Populate-Details
What are the different default triggers created when Master Deletes Property is set to isolated?
Master Deletes Property Resulting Triggers
---------------------------------------------------
Isolated On-Clear-Details
On-Populate-Details
What are the different default triggers created when Master Deletes Property is set to Cascade?
Master Deletes Property Resulting Triggers
---------------------------------------------------
Cascading On-Clear-Details
On-Populate-Details
Pre-delete
What is the diff. bet. setting up of parameters in reports 2.0 reports2.5?
LOVs can be attached to parameters in the reports 2.5 parameter form.
What are the difference between lov & list item?
Lov is a property where as list item is an item. A list item can have only one column, lov can have one or more columns.
What is the advantage of the library?
Libraries provide a convenient means of storing client-side program units and sharing them among multiple applications. Once you create a library, you can attach it to any other form, menu, or library modules. When you can call library program units from triggers menu items commands and user named routine, you write in the modules to which you have attach the library. When a library attaches another library, program units in the first library can reference program units in the attached library. Library support dynamic loading-that is library program units are loaded into an application only when needed. This can significantly reduce the run-time memory requirements of applications.
What is lexical reference? How can it be created?
Lexical reference is place_holder for text that can be embedded in a 
sql statements. A lexical reference can be created using & before the column or parameter name.
What is system.coordination_operation?
It represents the coordination causing event that occur on the master block in master-detail relation.
What is synchronize?
It is a terminal screen with the internal state of the form. It updates the screen display to reflect the information that oracle forms has in its internal representation of the screen.
What use of command line parameter cmd file?
It is a command line argument that allows you to specify a file that contain a set of arguments for r20run.
What is a Text_io Package?
It allows you to read and write information to a file in the 
file system.
What is forms_DDL?
Issues dynamic Sql statements at run time, including server side pl/SQl and DDL
How is link tool operation different bet. reports 2 & 2.5?
In Reports 2.0 the link tool has to be selected and then two fields to be linked are selected and the link is automatically created. In 2.5 the first field is selected and the link tool is then used to link the first field to the second field.
What are the different styles of activation of ole Objects?
In place activationExternal activation
How do you reference a Parameter?
In Pl/Sql, You can reference and set the values of form parameters using bind variables syntax. Ex. PARAMETER name = '' or :block.item = PARAMETER Parameter name
What is the difference between object embedding & linking in Oracle forms?
In Oracle forms, Embedded objects become part of the form module, and linked objects are references from a form module to a linked source file.
Name of the functions used to get/set canvas properties?
Get_view_property, Set_view_property
What are the built-ins that are used for setting the LOV properties at runtime? 
get_lov_property
set_lov_property
What are the built-ins used for processing rows?
Get_group_row_count(function)
Get_group_selection_count(function)
Get_group_selection(function)
Reset_group_selection(procedure)
Set_group_selection(procedure)
Unset_group_selection(procedure)
What are built-ins used for Processing rows?
GET_GROUP_ROW_COUNT(function)
GET_GROUP_SELECTION_COUNT(function)
GET_GROUP_SELECTION(function)
RESET_GROUP_SELECTION(procedure)
SET_GROUP_SELECTION(procedure)
UNSET_GROUP_SELECTION(procedure)
What are the built-in used for getting cell values?
Get_group_char_cell(function)
Get_groupcell(function)
Get_group_number_cell(function)
What are the built-ins used for Getting cell values?
GET_GROUP_CHAR_CELL (function)
GET_GROUPCELL(function)
GET_GROUP_NUMBET_CELL(function)
Atleast how many set of data must a data model have before a data model can be base on it?
Four
To execute row from being displayed that still use column in the row which property can be used?
Format trigger.
What are different types of modules available in oracle form?
Form module - a collection of objects and code routines Menu modules - a collection of menus and menu item commands that together make up an application menu library module - a collection of user named procedures, functions and packages that can be called from other modules in the application
What is the remove on exit property?
For a modelless window, it determines whether oracle forms hides the window automatically when the operators navigates to an item in the another window.
What is WHEN-Database-record trigger?
Fires when oracle forms first marks a record as an insert or an update. The trigger fires as soon as oracle forms determines through validation that the record should be processed by the next post or commit as an insert or update. c generally occurs only when the operators modifies the first item in the record, and after the operator attempts to navigate out of the item.
What is a difference between pre-select and pre-query?
Fires during the execute query and count query processing after oracle forms constructs the select statement to be issued, but before the statement is actually issued. The pre-query trigger fires just before oracle forms issues the select statement to the database after the operator as define the example records by entering the query criteria in enter query mode.Pre-query trigger fires before pre-select trigger.
What are built-ins associated with timers?
find_timercreate_timerdelete_timer
What are the built-ins used for finding object ID functions?
Find_group(function)
Find_column(function)
What are the built-ins used for finding Object ID function?
FIND_GROUP(function)
FIND_COLUMN(function)
Any attempt to navigate programmatically to disabled form in a call_form stack is allowed?
False
Use the Add_group_row procedure to add a row to a static record group 1. true or false?
False





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Sunday, July 17, 2011

Difference between 10g and 11g

1.Simplified and improved automatic memory management

2.New fault diagnosability infrastructure to prevent, detect, diagnose, and help resolve critical database errors

3.Invisible Indexes

4.Virtual columns

5.Enhanced security for password-based authentication by enabling use of mixed case in passwords.

6.Tablespace-level encryption

7.Ability to online redefine tables that have materialized view logs


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Saturday, July 16, 2011

Create database manually

Create database manually in windows
or Create database through command line

STEP1: c:\> set oracle sid= rose 

STEP2:  create Pfile


 pfile content these parameter 
 "db_NAME=ROSE
   SGA_TARGET=600M
   COMPATIBLE =10.2.0 (your db version)"

Step3: (for windows we need to create instance)


create instance

"C:\>oradim -new -sid ROSE -SRVCOracleServiceROSE -STARTMODE auto -SRVCSTART system -PFILE  C:\ORACLE_HOME\dat
abase\INITrose.ORA"



Instance created.


step 4:  c:\>sqlplus  sys as sysdba



step 5:   SQL> startup nomount


 step 6: SQL> create database Rose;




step 7:  create datafile system
               SQL> alter tablespace
               system add
               datafile 'C:\%ORACLE_HOME%\rose\system01.dbf '
                size 500m

Tablespace altered.

Step 8: create datafile SYSAUX

              SQL>alter tablespace
             SYSAUX add
             datafile 'C:\%ORACLE_HOME%\rose\SYSAUX01.dbf '
             size 500m

Tablespace altered.
 
STEP 9:  Create temporary tablespace
                 SQL> CREATE TEMPORARY tablespace temp
                 tempfile 'C:\%ORACLE_HOME%\rose\tmp01.tmp '
     size 100m
 Tablespace created.


 Step 10:  add log files Group
                  SQL>alter database
                  add logfile
                  group 2 'C:\%ORACLE_HOME%\rose\log06.log' SIZE 25M,
 
                 group 3 'C:\>ORACLE_HOME%\oradata\rose\log07.log' SIZE 25M
 
Step 11:NOW RUN

SQL>@%ORACLE_HOME%\rdbms\admin\CATALOG.SQL


SQL>@%ORACLE_HOME%\rdbms\admin\CATAPROC.SQL

DONE .......


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Wednesday, July 13, 2011

Few Oracle SQL Command

Increase the Size of Tablespace



If you want to increase the size of tablespace, its so simple. You can do this by enterprise manager console. Increase the size of datafile for particular tablespace.

OR

For Example

ALTER DATABASE
DATAFILE ‘(datafile path)/u01/oradata/ userdata03. dbf’
RESIZE 200M;

If you don’t have any free space on that partition of disk then you can add another datafile on the other partition  for particular tablespace.

For example

ALTER TABLESPACE app_data
ADD DATAFILE ‘/u01/oradata/ userdata03. dbf’
SIZE 200M;
-----------------------------------------------------------------------------------------

Tablespace used in Percentage 




# login oracle with sqlplus as  sysadm user
# conn as sysdba

select a.TABLESPACE_NAME,
a.BYTES bytes_used,
b.BYTES bytes_free,
b.largest,
round(((a.BYTES-b.BYTES)/a.BYTES)*100,2) percent_used
from
(
select TABLESPACE_NAME,
sum(BYTES) BYTES
from dba_data_files
group by TABLESPACE_NAME
)
a,
(
select TABLESPACE_NAME,
sum(BYTES) BYTES ,
max(BYTES) largest
from dba_free_space
group by TABLESPACE_NAME
)
b
where a.TABLESPACE_NAME=b.TABLESPACE_NAME
 and round(((a.BYTES-b.BYTES)/a.BYTES)*100,2)  > 75
order by ((a.BYTES-b.BYTES)/a.BYTES) desc
/







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Friday, July 8, 2011

General ORACLE DBA interview Question

1. What is an Oracle Instance?
    An instance is the (executed) Oracle software (Oracle processes) and the memory they use (SGA).             It  is  the instance that manipulates the data stored in the database.

2. What information is stored in Control File?
The database name
The timestamp of database creation
  The names and locations of associated datafiles and redo log files
  Tablespace information
  Datafile offline ranges
  The log history
  Archived log information
  Backup set and backup piece information
  Backup datafile and redo log information
  Datafile copy information
  The current log sequence number


3. When you start an Oracle DB which file is accessed first?
Oracle first open and reads the initialization parameter file (init.ora).
   


4. What is the Job of SMON, PMON processes?
PMON—It cleaned up the failed processes BY
>> Rolling back the transaction
>> Releasing all currently held table  or row  locks
>> freeing other resource currently held by the user
>>Restart the dead dispatcher


SMON—if the oracle instance fails , any information that in SGA that has not been written  to the disk is cost .
>> the background process smon automatic perform instance recovery when the database is reopened.
>>Instance recovery
•    Roll forward changes in the redolog
•    Open the database for user access
•    Roll back the uncommitted transaction also perform
•    It combines or coalesces, adjacent area of free space in the datafile .
•    Dislocate the temporary segment  


5. What is Instance Recovery?


 Instance recovery
•    Roll forward changes in the redolog
•    Open the database for user access
•    Roll back the uncommitted transaction also perform
•    It combines or coalesces, adjacent area of free space in the datafile .
•    Dislocate the temporary segment 

 
6. What is written in Redo Log Files?

# Log writer (LGWR) writes redo log buffer contents Into Redo Log FIles. Log writer does this every three seconds, when the redo log buffer is 1/3 full and immediately before the Database Writer (DBWn) writes its changed buffers into the datafile. 






7. How do you control number of Datafiles one can have in an Oracle database?


8. How many Maximum Datafiles can there be in an Oracle Database?

In a database there can have maximum 65533 data files.
 
9. What is a Tablespace?

A tablespace is a logical group of data files in a database. A database typically contains at least one tablespace, and usually two or more. Within the database, the tablespace plays a role similar to that of a folder on the hard drive of a computer.

Some database programs, such as Oracle, automatically create a tablespace called SYSTEM that contains general information about the structure and contents of the database. A small database can be entirely contained in the SYSTEM tablespace, but in most cases, user datais placed in other tablespaces.

There is no relationship between a tablespace and a schema. Objects in the same schema can be in different tablespaces, and a tablespace can hold objects from different schemas.

10. What is the purpose of Redo Log files?

11. Which default Database roles are created when you create a Database?

12. What is a Checkpoint?

13. Which Process reads data from Datafiles?

14. Which Process writes data in Datafiles?

15. Can you make a Datafile auto extendible. If yes, how?

16. What is a Shared Pool?

17. What is kept in the Database Buffer Cache?

18. How many maximum Redo Logfiles one can have in a Database?

19. What is difference between PFile and SPFile?

20. What is PGA_AGGREGRATE_TARGET parameter?

21. Large Pool is used for what?

22. What is PCT Increase setting?

23. What is PCTFREE and PCTUSED Setting?

24. What is Row Migration and Row Chaining?

25. What is 01555 - Snapshot Too Old error and how do you avoid it?

26. What is a Locally Managed Tablespace?

27. Can you audit SELECT statements?

28. What does DBMS_FGA package do?

29. What is Cost Based Optimization?

30. How often you should collect statistics for a table?

31. How do you collect statistics for a table, schema and Database?

32. Can you make collection of Statistics for tables automatic?

33. On which columns you should create Indexes?

34. What type of Indexes are available in Oracle?

35. What is B-Tree Index?

36. A table is having few rows, should you create indexes on this table?

37. A Column is having many repeated values which type of index you should create on this
column, if you have to?

38. When should you rebuilt indexes?

39. Can you built indexes online?

40. Can you see Execution Plan of a statement.

41. A table is created with the following setting 
storage (initial 200k next 200k minextents 2 maxextents 100 pctincrease

40) What will be size of 4th extent?

42. What is DB Buffer Cache Advisor?

43. What is STATSPACK tool?

44. Can you change SHARED_POOL_SIZE online?

45. Can you Redefine a table Online?

46. Can you assign Priority to users?

47. You want users to change their passwords every 2 months. How do you enforce this?

48. How do you delete duplicate rows in a table?

49. What is Automatic Management of Segment Space setting?

50. What is the difference between DELETE and TRUNCATE statements?

51. What is COMPRESS and CONSISTENT setting in EXPORT utility?

52. What is the difference between Direct Path and Convention Path loading?

53. Can you disable and enable Primary key?

54. What is an Index Organized Table?

55. What is a Global Index and Local Index?

56. What is the difference between Range Partitioning and Hash Partitioning?

57. What is difference between Multithreaded/Shared Server and Dedicated Server?

58. Can you import objects from Oracle ver. 9i to 10g?

59. How do you move tables from one tablespace to another tablespace?

60. How do see how much space is used and free in a tablespace?




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Sunday, June 26, 2011

how to change sys password in Oracle 10g

 To Change the ""SYS"  Password

SQL> conn sys as sysdba
Enter password: (null) no need to give anything
Connected.
SQL> passw system
Changing password for system
New password: (new password)
Retype new password:
(new password)
Password changed
SQL> conn system/
(new password) 
Connected.
SQL> passw sys
Changing password for sys
New password: (new sys password )
Retype new password:
(new sys password )
Password changed
SQL>





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Wednesday, June 22, 2011

MANAGE USER

HOW To create USER
SQL>create user chetan
  2  identified by c
  3  default tablsespace SYSTEM
  4  temporary tablespace TEMP
  5  quota 20 m on SYSTEM
  6  password expire;
-------------

change system tablespace 

SQL> create user chetan
  2  identified by c
  3  default tablespace EXAMPLE
  4  temporary tablespace TEMP
  5  quota 15m on EXAMPLE
  6  password expire;

User created.

now its created ...


TO see the session privilege

SQL>select * from session_privs;

PRIVILEGE
----------------------------------------
CREATE SESSION

---------------------------------------------------


How to create Profile

______________________________
CREATION OF PROFILE
______________________________
create profile  profile_name limit
  sessions_per_user                 2   --
  cpu_per_session               10000   -- hunderth of seconds
  cpu_per_call                      1   -- hunderth of seconds
  connect_time              unlimited   -- minutes
  idle_time                        30   -- minutes
  logical_reads_per_session   default   -- db blocks
  logical_reads_per_call      default   -- db blocks
  -- composite_limit          default   --
  private_sga                     20M   --
  failed_login_attempts             3   --
  password_life_time               30   -- days
  password_reuse_time              12   --
  password_reuse_max        unlimited   --
  password_lock_time          default   -- days
  password_grace_time               2   -- days
  password_verify_function       null;



EXAMPLE Is blow


SQL >create profile ram limit
    sessions_per_user 2
    connect_time 30
    idle_time 30
    failed_login_attempts 4
    password_life_time 2
    password_reuse_time 5
    password_grace_time 1;
    
 Profile created.

-----------


how to see a profile

SQL> show user
USER is "SYS"

SQL> desc dba_profiles
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 PROFILE                                   NOT NULL VARCHAR2(30)
 RESOURCE_NAME                             NOT NULL VARCHAR2(32)
 RESOURCE_TYPE                                      VARCHAR2(8)
 LIMIT                                              VARCHAR2(40)

SQL> select profile from dba_profiles;

PROFILE
------------------------------
DEFAULT
DEFAULT
DEFAULT
DEFAULT
DEFAULT
DEFAULT
DEFAULT
DEFAULT
DEFAULT
DEFAULT
DEFAULT

PROFILE
------------------------------
DEFAULT
DEFAULT
DEFAULT
DEFAULT
DEFAULT
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE

PROFILE
------------------------------
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
MONITORING_PROFILE
RAM

PROFILE
------------------------------
RAM
RAM
RAM
RAM
RAM
RAM
RAM
RAM
RAM
RAM
RAM

PROFILE
------------------------------
RAM
RAM
RAM
RAM

48 rows selected.
---------------------------------------------------------------------------
SQL> select * from dba_profiles where profile='RAM';

PROFILE                        RESOURCE_NAME                    RESOURCE
------------------------------ -------------------------------- --------
LIMIT
----------------------------------------
RAM                            COMPOSITE_LIMIT                  KERNEL
DEFAULT

RAM                            SESSIONS_PER_USER                KERNEL
2

RAM                            CPU_PER_SESSION                  KERNEL
DEFAULT


PROFILE                        RESOURCE_NAME                    RESOURCE
------------------------------ -------------------------------- --------
LIMIT
----------------------------------------
RAM                            CPU_PER_CALL                     KERNEL
DEFAULT

RAM                            LOGICAL_READS_PER_SESSION        KERNEL
DEFAULT

RAM                            LOGICAL_READS_PER_CALL           KERNEL
DEFAULT


PROFILE                        RESOURCE_NAME                    RESOURCE
------------------------------ -------------------------------- --------
LIMIT
----------------------------------------
RAM                            IDLE_TIME                        KERNEL
30

RAM                            CONNECT_TIME                     KERNEL
30

RAM                            PRIVATE_SGA                      KERNEL
DEFAULT


PROFILE                        RESOURCE_NAME                    RESOURCE
------------------------------ -------------------------------- --------
LIMIT
----------------------------------------
RAM                            FAILED_LOGIN_ATTEMPTS            PASSWORD
4

RAM                            PASSWORD_LIFE_TIME               PASSWORD
2

RAM                            PASSWORD_REUSE_TIME              PASSWORD
5


PROFILE                        RESOURCE_NAME                    RESOURCE
------------------------------ -------------------------------- --------
LIMIT
----------------------------------------
RAM                            PASSWORD_REUSE_MAX               PASSWORD
DEFAULT

RAM                            PASSWORD_VERIFY_FUNCTION         PASSWORD
DEFAULT

RAM                            PASSWORD_LOCK_TIME               PASSWORD
DEFAULT


PROFILE                        RESOURCE_NAME                    RESOURCE
------------------------------ -------------------------------- --------
LIMIT
----------------------------------------
RAM                            PASSWORD_GRACE_TIME              PASSWORD
1


16 rows selected.
-----------------------------------------







any mistake is there or u wanna give any suggestion so please write to me ............