DBA Interview Questions
DBA
Interview Questions Part-I
March 13, 2006
1. What is Log Switch? - The point at which ORACLE ends writing to one online redo log
file and begins writing to another is called a log switch.
2. What is On-line Redo Log? - The On-line Redo Log is a set of tow or more on-line redo files
that record all committed changes made to the database. Whenever a transaction
is committed, the corresponding redo entries temporarily stores in redo log
buffers of the SGA are written to an on-line redo log file by the background
process LGWR. The on-line redo log files are used in cyclical fashion.
3. Which parameter specified in
the DEFAULT STORAGE clause of CREATE TABLESPACE cannot be altered after
creating the tablespace? - All the default
storage parameters defined for the tablespace can be changed using the ALTER
TABLESPACE command. When objects are created their INITIAL and MINEXTENS values
cannot be changed.
4. What are the steps involved in
Database Startup? - Start an instance,
Mount the Database and Open the Database.
5. What are the steps involved in
Instance Recovery? - Rolling forward to
recover data that has not been recorded in data files, yet has been recorded in
the on-line redo log, including the contents of rollback segments. Rolling back
transactions that have been explicitly rolled back or have not been committed
as indicated by the rollback segments regenerated in step a. Releasing any
resources (locks) held by transactions in process at the time of the failure.
Resolving any pending distributed transactions undergoing a two-phase commit at
the time of the instance failure.
6. Can Full Backup be performed
when the database is open? - No.
7. What are the different modes of
mounting a Database with the Parallel Server? - Exclusive Mode If the first instance that mounts a database does
so in exclusive mode, only that Instance can mount the database. Parallel Mode
If the first instance that mounts a database is started in parallel mode, other
instances that are started in parallel mode can also mount the database.
8. What are the advantages of
operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG
mode? - Complete database recovery from disk
failure is possible only in ARCHIVELOG mode. Online database backup is possible
only in ARCHIVELOG mode.
9. What are the steps involved in
Database Shutdown? - Close the Database,
Dismount the Database and Shutdown the Instance.
10. What is Archived Redo Log? - Archived Redo Log consists of Redo Log files that have archived
before being reused.
11. What is Restricted Mode of
Instance Startup? - An instance can be
started in (or later altered to be in) restricted mode so that when the
database is open connections are limited only to those whose user accounts have
been granted the RESTRICTED SESSION system privilege.
12. What is Partial Backup? - A Partial Backup is any operating system backup short of a full
backup, taken while the database is open or shut down.
13. What is Mirrored on-line Redo
Log? - A mirrored on-line redo log consists
of copies of on-line redo log files physically located on separate disks,
changes made to one member of the group are made to all members.
14. What is Full Backup? - A full backup is an operating system backup of all data files,
on- line redo log files and control file that constitute ORACLE database and
the parameter.
15. Can a View based on another
View? - Yes.
16. Can a Tablespace hold objects
from different Schemes? - Yes.
17. Can objects of the same Schema
reside in different tablespaces? - Yes.
18. What is the use of Control
File? - When an instance of an ORACLE database
is started, its control file is used to identify the database and redo log
files that must be opened for database operation to proceed. It is also used in
database recovery.
19. Do View contain Data? - Views do not contain or store data.
20. What are the Referential
actions supported by FOREIGN KEY integrity constraint? - UPDATE and DELETE Restrict - A referential integrity rule that
disallows the update or deletion of referenced data. DELETE Cascade - When a
referenced row is deleted all associated dependent rows are deleted.
21. What are the type of Synonyms? - There are two types of Synonyms Private and Public
22. What is a Redo Log? - The set of Redo Log files YSDATE,UID,USER or USERENV SQL
functions, or the pseudo columns LEVEL or ROWNUM.
23. What is an Index Segment? - Each Index has an Index segment that stores all of its data.
24. Explain the relationship among
Database, Tablespace and Data file.? - Each databases logically divided into one or more tablespaces
one or more data files are explicitly created for each tablespace
25. What are the different type of
Segments? - Data Segment, Index
Segment, Rollback Segment and Temporary Segment.
26. What are Clusters? - Clusters are groups of one or more tables physically stores
together to share common columns and are often used together.
27. What is an Integrity
Constrains? - An integrity
constraint is a declarative way to define a business rule for a column of a
table.
28. What is an Index? - An Index is an optional structure associated with a table to
have direct access to rows, which can be created to increase the performance of
data retrieval. Index can be created on one or more columns of a table.
29. What is an Extent? - An Extent is a specific number of contiguous data blocks,
obtained in a single allocation, and used to store a specific type of
information.
30. What is a View? - A view is a virtual table. Every view has a Query attached to
it. (The Query is a SELECT statement that identifies the columns and rows of
the table(s) the view uses.)
31. What is Table? - A table is the basic unit of data storage in an ORACLE database.
The tables of a database hold all of the user accessible data. Table data is
stored in rows and columns.
32. What is a Synonym? - A synonym is an alias for a table, view, sequence or program
unit.
33. What is a Sequence? - A sequence generates a serial list of unique numbers for
numerical columns of a database’s tables.
34. What is a Segment? - A segment is a set of extents allocated for a certain logical
structure.
35. What is schema? - A schema is collection of database objects of a User.
36. Describe Referential Integrity? - A rule defined on a column (or set of columns) in one table that
allows the insert or update of a row only if the value for the column or set of
columns (the dependent value) matches a value in a column of a related table
(the referenced value). It also specifies the type of data manipulation allowed
on referenced data and the action to be performed on dependent data as a result
of any action on referenced data.
37. What is Hash Cluster? - A row is stored in a hash cluster based on the result of
applying a hash function to the row’s cluster key value. All rows with
the same hash key value are stores together on disk.
38. What is a Private Synonyms? - A Private Synonyms can be accessed only by the owner.
39. What is Database Link? - A database link is a named object that describes a
“path†from one database to another.
40. What is a Tablespace? - A database is divided into Logical Storage Unit called
tablespaces. A tablespace is used to grouped related logical structures
together
41. What is Rollback Segment? - A Database contains one or more Rollback Segments to temporarily
store “undo†information.
42. What are the Characteristics of
Data Files? - A data file can be
associated with only one database. Once created a data file can’t change
size. One or more data files form a logical unit of database storage called a
tablespace.
43. How to define Data Block size? - A data block size is specified for each ORACLE database when the
database is created. A database users and allocated free database space in
ORACLE datablocks. Block size is specified in INIT.ORA file and can’t be
changed latter.
44. What does a Control file
Contain? - A Control file
records the physical structure of the database. It contains the following
information. Database Name Names and locations of a database’s files and
redolog files. Time stamp of database creation.
45. What is difference between
UNIQUE constraint and PRIMARY KEY constraint? - A column defined as UNIQUE can contain Nulls while a column
defined as PRIMARY KEY can’t contain Nulls. 47.What is Index Cluster? - A Cluster with an index on the
Cluster Key 48.When does a Transaction end? -
When it is committed or Rollbacked.
46. What is the effect of setting
the value “ALL_ROWS†for OPTIMIZER_GOAL parameter
of the ALTER SESSION command? - What are the factors
that affect OPTIMIZER in choosing an Optimization approach? - Answer The OPTIMIZER_MODE
initialization parameter Statistics in the Data Dictionary the OPTIMIZER_GOAL
parameter of the ALTER SESSION command hints in the statement.
47. What is the effect of setting
the value “CHOOSE†for OPTIMIZER_GOAL, parameter of the ALTER SESSION
Command? - The Optimizer chooses
Cost_based approach and optimizes with the goal of best throughput if
statistics for atleast one of the tables accessed by the SQL statement exist in
the data dictionary. Otherwise the OPTIMIZER chooses RULE_based approach.
48. What is the function of
Optimizer? - The goal of the
optimizer is to choose the most efficient way to execute a SQL statement.
49. What is Execution Plan? - The combinations of the steps the optimizer chooses to execute a
statement is called an execution plan.
50. What are the different
approaches used by Optimizer in choosing an execution plan? - Rule-based and Cost-based.
DBA
Interview Questions - Part 2
March 14, 2006
1. What does ROLLBACK do? - ROLLBACK retracts any of the changes resulting from the SQL
statements in the transaction.
2. What is SAVE POINT? - For long transactions that contain many SQL statements,
intermediate markers or savepoints can be declared which can be used to divide
a transaction into smaller parts. This allows the option of later rolling back
all work performed from the current point in the transaction to a declared
savepoint within the transaction.
3. What are the values that can be
specified for OPTIMIZER MODE Parameter? - COST and RULE.
4. What is COST-based approach to
optimization? - Considering available
access paths and determining the most efficient execution plan based on
statistics in the data dictionary for the tables accessed by the statement and
their associated clusters and indexes.
5. What does COMMIT do? - COMMIT makes permanent the changes resulting from all SQL
statements in the transaction. The changes made by the SQL statements of a
transaction become visible to other user sessions transactions that start only
after transaction is committed.
6. What is RULE-based approach to
optimization? - Choosing an executing
plan based on the access paths available and the ranks of these access paths.
7. What are the values that can be
specified for OPTIMIZER_GOAL parameter of the ALTER SESSION Command? - CHOOSE,ALL_ROWS,FIRST_ROWS and RULE.
8. Define Transaction? - A Transaction is a logical unit of work that comprises one or
more SQL statements executed by a single user.
9. What is Read-Only Transaction? - A Read-Only transaction ensures that the results of each query
executed in the transaction are consistent with respect to the same point in
time.
10. What is a deadlock? - Explain . Two processes waiting to update the rows of a table
which are locked by the other process then deadlock arises. In a database
environment this will often happen because of not issuing proper row lock
commands. Poor design of front-end application may cause this situation and the
performance of server will reduce drastically. These locks will be released
automatically when a commit/rollback operation performed or any one of this
processes being killed externally.
11. What is a Schema? - The set of objects owned by user account is called the schema.
12. What is a cluster Key? - The related columns of the tables are called the cluster key.
The cluster key is indexed using a cluster index and its value is stored only
once for multiple tables in the cluster.
13. What is Parallel Server? - Multiple instances accessing the same database (Only In
Multi-CPU environments)
14. What are the basic element of
Base configuration of an oracle Database? - It consists of one or more data files. one or more control
files. two or more redo log files. The Database contains multiple users/schemas
one or more rollback segments one or more tablespaces Data dictionary tables
User objects (table, indexes, views etc.,) The server that access the database
consists of SGA (Database buffer, Dictionary Cache Buffers, Redo log buffers,
Shared SQL pool) SMON (System MONito) PMON (Process MONitor) LGWR (LoG Write)
DBWR (Data Base Write) ARCH (ARCHiver) CKPT (Check Point) RECO Dispatcher User
Process with associated PGS
15. What is clusters? - Group of tables physically stored together because they share
common columns and are often used together is called Cluster.
16. What is an Index? - How it is implemented in Oracle Database? - An index is a database structure
used by the server to have direct access of a row in a table. An index is
automatically created when a unique of primary key constraint clause is
specified in create table command (Ver 7.0)
17. What is a Database instance? - Explain A database instance (Server) is a set of memory
structure and background processes that access a set of database files. The
process can be shared by all users. The memory structure that are used to store
most queried data from database. This helps up to improve database performance
by decreasing the amount of I/O performed against data file.
18. What is the use of ANALYZE
command? - To perform one of
these function on an index, table, or cluster: - To collect statistics about
object used by the optimizer and store them in the data dictionary. - To delete
statistics about the object used by object from the data dictionary. - To
validate the structure of the object.. - To identify migrated and chained rows
off the table or cluster.
19. What is default tablespace? - The Tablespace to contain schema objects created without
specifying a tablespace name.
20. What are the system resources
that can be controlled through Profile? - The number of concurrent sessions the user can establish the CPU
processing time available to the user’s session the CPU processing time
available to a single call to ORACLE made by a SQL statement the amount of
logical I/O available to the user’s session the amount of logical I/O
available to a single call to ORACLE made by a SQL statement the allowed amount
of idle time for the user’s session the allowed amount of connect time
for the user’s session.
21. What is Tablespace Quota? - The collective amount of disk space available to the objects in
a schema on a particular tablespace.
22. What are the different Levels
of Auditing? - Statement Auditing,
Privilege Auditing and Object Auditing.
23. What is Statement Auditing? - Statement auditing is the auditing of the powerful system
privileges without regard to specifically named objects
24. What are the database
administrators utilities available? - SQL * DBA - This allows DBA to monitor and control an ORACLE
database. SQL * Loader - It loads data from standard operating system files
(Flat files) into ORACLE database tables. Export (EXP) and Import (imp)
utilities allow you to move existing data in ORACLE format to and from ORACLE
database.
25. How can you enable automatic
archiving? - Shut the database
Backup the database Modify/Include LOG_ARCHIVE_START_TRUE in init.ora file.
Start up the database.
26. What are roles? - How can we implement roles? -
Roles are the easiest way to grant and manage common privileges needed by
different groups of database users. Creating roles and assigning provides to
roles. Assign each role to group of users. This will simplify the job of
assigning privileges to individual users.
27. What are Roles? - Roles are named groups of related privileges that are granted to
users or other roles.
28. What are the use of Roles? - REDUCED GRANTING OF PRIVILEGES - Rather than explicitly granting
the same set of privileges to many users a database administrator can grant the
privileges for a group of related users granted to a role and then grant only
the role to each member of the group. DYNAMIC PRIVILEGE MANAGEMENT - When the
privileges of a group must change, only the privileges of the role need to be
modified. The security domains of all users granted the group’s role
automatically reflect the changes made to the role. SELECTIVE AVAILABILITY OF
PRIVILEGES - The roles granted to a user can be selectively enable (available
for use) or disabled (not available for use). This allows specific control of a
user’s privileges in any given situation. APPLICATION AWARENESS - A
database application can be designed to automatically enable and disable
selective roles when a user attempts to use the application.
29. What is Privilege Auditing? - Privilege auditing is the auditing of the use of powerful system
privileges without regard to specifically named objects.
30. What is Object Auditing? - Object auditing is the auditing of accesses to specific schema
objects without regard to user.
31. What is Auditing? - Monitoring of user access to aid in the investigation of
database use.
32. What are the responsibilities
of a Database Administrator?
§
Installing and upgrading the Oracle Server and application tools.
§
Allocating system storage and planning future storage requirements
for the database system.
§
Managing primary database structures (tablespaces)
§
Managing primary objects (table, views, indexes)
§
Enrolling users and maintaining system security.
§
Ensuring compliance with Oracle license agreement
§
Controlling and monitoring user access to the database.
§
Monitoring and optimizing the performance of the database.
§
Planning for backup and recovery of database information.
§
Maintain archived data on tape
§
Backing up and restoring the database.
§
Contacting Oracle Corporation for technical support.
33. What is a trace file and how is
it created? - Each server and
background process can write an associated trace file. When an internal error
is detected by a process or user process, it dumps information about the error
to its trace. This can be used for tuning the database.
34. What is a profile? - Each database user is assigned a Profile that specifies
limitations on various system resources available to the user.
35. How will you enforce security
using stored procedures? - Don’t grant
user access directly to tables within the application. Instead grant the
ability to access the procedures that access the tables. When procedure
executed it will execute the privilege of procedures owner. Users cannot access
tables except via the procedure
DBA
Interview Questions - Part 3
March 15, 2006
1. What are the dictionary tables
used to monitor a database spaces? - DBA_FREE_SPACE
DBA_SEGMENTS DBA_DATA_FILES.
2. What are the roles and user
accounts created automatically with the database? - DBA - role Contains all database system privileges. SYS user
account - The DBA role will be assigned to this account. All of the base tables
and views for the database’s dictionary are store in this schema and are
manipulated only by ORACLE. SYSTEM user account - It has all the system
privileges for the database and additional tables and views that display
administrative information and internal tables and views used by oracle tools
are created using this username.
3. What are the minimum parameters
should exist in the parameter file (init.ora)? - DB NAME - Must set to a text string of no more than 8 characters
and it will be stored inside the datafiles, redo log files and control files
and control file while database creation. DB_DOMAIN - It is string that
specifies the network domain where the database is created. The global database
name is identified by setting these parameters (DB_NAME & DB_DOMAIN)
CONTORL FILES - List of control filenames of the database. If name is not
mentioned then default name will be used. DB_BLOCK_BUFFERS - To determine the
no of buffers in the buffer cache in SGA. PROCESSES - To determine number of
operating system processes that can be connected to ORACLE concurrently. The
value should be 5 (background process) and additional 1 for each user.
ROLLBACK_SEGMENTS - List of rollback segments an ORACLE instance acquires at
database startup. Also optionally LICENSE_MAX_SESSIONS,LICENSE_SESSION_WARNING
and LICENSE_MAX_USERS.
4. How can we specify the Archived
log file name format and destination? - By setting the following values in init.ora file.
LOG_ARCHIVE_FORMAT = arch %S/s/T/tarc (%S - Log sequence number and is zero
left padded, %s - Log sequence number not padded. %T - Thread number left-zero-
padded and %t - Thread number not padded). The file name created is arch 0001
are if %S is used. LOG_ARCHIVE_DEST = path.
5. What is user Account in Oracle
database? - An user account is
not a physical structure in Database but it is having important relationship to
the objects in the database and will be having certain privileges. 95. When
will the data in the snapshot log be used? -
We must be able to create a after row trigger on table (i.e., it should be not
be already available) After giving table privileges. We cannot specify snapshot
log name because oracle uses the name of the master table in the name of the
database objects that support its snapshot log. The master table name should be
less than or equal to 23 characters. (The table name created will be
MLOGS_tablename, and trigger name will be TLOGS name).
6. What dynamic data replication? - Updating or Inserting records in remote database through
database triggers. It may fail if remote database is having any problem.
7. What is Two-Phase Commit? - Two-phase commit is mechanism that guarantees a distributed
transaction either commits on all involved nodes or rolls back on all involved
nodes to maintain data consistency across the global distributed database. It
has two phase, a Prepare Phase and a Commit Phase.
8. How can you Enforce Referential
Integrity in snapshots? - Time the references
to occur when master tables are not in use. Peform the reference the manually
immdiately locking the master tables. We can join tables in snopshots by
creating a complex snapshots that will based on the master tables.
9. What is a SQL * NET? - SQL *NET is ORACLE’s mechanism for interfacing with the
communication protocols used by the networks that facilitate distributed
processing and distributed databases. It is used in Clint-Server and
Server-Server communications.
10. What is a SNAPSHOT? - Snapshots are read-only copies of a master table located on a
remote node which is periodically refreshed to reflect changes made to the
master table.
11. What is the mechanism provided
by ORACLE for table replication? - Snapshots and
SNAPSHOT LOGs
12. What is snapshots? - Snapshot is an object used to dynamically replicate data between
distribute database at specified time intervals. In ver 7.0 they are read only.
13. What are the various type of
snapshots? - Simple and Complex.
14. Describe two phases of
Two-phase commit? - Prepare phase - The
global coordinator (initiating node) ask a participants to prepare (to promise
to commit or rollback the transaction, even if there is a failure) Commit -
Phase - If all participants respond to the coordinator that they are prepared,
the coordinator asks all nodes to commit the transaction, if all participants
cannot prepare, the coordinator asks all nodes to roll back the transaction.
15. What is snapshot log? - It is a table that maintains a record of modifications to the
master table in a snapshot. It is stored in the same database as master table
and is only available for simple snapshots. It should be created before
creating snapshots.
16. What are the benefits of
distributed options in databases? - Database on other
servers can be updated and those transactions can be grouped together with
others in a logical unit. Database uses a two phase commit.
17. What are the options available
to refresh snapshots? - COMPLETE - Tables are
completely regenerated using the snapshots query and the master tables every
time the snapshot referenced. FAST - If simple snapshot used then a snapshot
log can be used to send the changes to the snapshot tables. FORCE - Default
value. If possible it performs a FAST refresh; Otherwise it will perform a
complete refresh.
18. What is a SNAPSHOT LOG? - A snapshot log is a table in the master database that is
associated with the master table. ORACLE uses a snapshot log to track the rows
that have been updated in the master table. Snapshot logs are used in updating
the snapshots based on the master table.
19. What is Distributed database? - A distributed database is a network of databases managed by
multiple database servers that appears to a user as single logical database.
The data of all databases in the distributed database can be simultaneously
accessed and modified.
20. How can we reduce the network
traffic? - Replication of data
in distributed environment. - Using snapshots to replicate data. - Using remote
procedure calls.
21. Differentiate simple and
complex, snapshots? - A simple snapshot is
based on a query thaat does not contains GROUP BY clauses, CONNECT BY clauses,
JOINs, sub-query or snapshot of operations. - A complex snapshots contain at
least any one of the above.
22. What are the Built-ins used for
sending Parameters to forms? - You can pass
parameter values to a form when an application executes the call_form,
New_form, Open_form or Run_product.
23. Can you have more than one
content canvas view attached with a window? - Yes. Each window you create must have at least one content
canvas view assigned to it. You can also create a window that has manipulated
content canvas view. At run time only one of the content canvas views assign to
a window is displayed at a time.
DBA
Interview Questions - Part 4
March 16, 2006
1. Is the After report trigger
fired if the report execution fails? - Yes.
2. Does a Before form trigger fire
when the parameter form is suppressed? - Yes.
3. Is it possible to split the
print reviewer into more than one region? - Yes
4. Is it possible to center an
object horizontally in a repeating frame that has a variable horizontal size? - Yes
5. For a field in a repeating
frame, can the source come from the column which does not exist in the data
group which forms the base for the frame? - Yes
6. Can a field be used in a report
without it appearing in any data group? - Yes
7. The join defined by the default
data link is an outer join yes or no? - Yes
8. Can a formula column referred
to columns in higher group? - Yes
9. Can a formula column be
obtained through a select statement? - Yes
10. Is it possible to insert
comments into sql statements return in the data model editor? - Yes
11. Is it possible to disable the
parameter from while running the report? - Yes
12. When a form is invoked with
call_form, Does oracle forms issues a save point? - Yes
13. Can a property clause itself be
based on a property clause? - Yes
14. If a parameter is used in a
query without being previously defined, what diff. exist between report 2.0 and
2.5 when the query is applied? - While both reports
2.0 and 2.5 create the parameter, report 2.5 gives a message that a bind
parameter has been created.
15. What are the SQL clauses
supported in the link property sheet? - Where start with having.
16. What is trigger associated with
the timer? - When-timer-expired.
17. What are the trigger associated
with image items? - When-image-activated
fires when the operators double clicks on an image itemwhen-image-pressed fires
when an operator clicks or double clicks on an image item
18. What are the different windows
events activated at runtimes? - When_window_activated
When_window_closed When_window_deactivated When_window_resized Within this
triggers, you can examine the built in system variable system. event_window to
determine the name of the window for which the trigger fired.
19. When do you use data parameter
type? - When the value of a data parameter
being passed to a called product is always the name of the record group defined
in the current form. Data parameters are used to pass data to produts invoked
with the run_product built-in subprogram.
20. What is difference between
open_form and call_form? - when one form invokes
another form by executing open_form the first form remains displayed, and
operators can navigate between the forms as desired. when one form invokes
another form by executing call_form, the called form is modal with respect to
the calling form. That is, any windows that belong to the calling form are
disabled, and operators cannot navigate to them until they first exit the
called form.
21. What is new_form built-in? - When one form invokes another form by executing new_form oracle
form exits the first form and releases its memory before loading the new form
calling new form completely replace the first with the second. If there are
changes pending in the first form, the operator will be prompted to save them
before the new form is loaded.
22. What is the “LOV of Validation”
Property of an item? - What is the use of
it? - When LOV for Validation is
set to True, Oracle Forms compares the current value of the text item to the
values in the first column displayed in the LOV. Whenever the validation event
occurs. If the value in the text item matches one of the values in the first
column of the LOV, validation succeeds, the LOV is not displayed, and
processing continues normally. If the value in the text item does not match one
of the values in the first column of the LOV, Oracle Forms displays the LOV and
uses the text item value as the search criteria to automatically reduce the
list.
23. What is the diff. when Flex
mode is mode on and when it is off? - When flex mode is on, reports automatically resizes the parent
when the child is resized.
24. What is the diff. when confine
mode is on and when it is off? - When confine mode is
on, an object cannot be moved outside its parent in the layout.
25. What are visual attributes? - Visual attributes are the font, color, pattern proprieties that
you set for form and menu objects that appear in your application interface.
26. Which of the two views should
objects according to possession? - view by structure.
27. What are the two types of views
available in the object navigator (specific to report 2.5)? - View by structure and view by type .
28. What are the vbx controls? - Vbx control provide a simple method of building and enhancing
user interfaces. The controls can use to obtain user inputs and display program
outputs.vbx control where originally develop as extensions for the ms visual
basic environments and include such items as sliders, rides and knobs.
29. What is the use of
transactional triggers? - Using transactional
triggers we can control or modify the default functionality of the oracle
forms.
30. How do you create a new session
while open a new form? - Using open_form
built-in setting the session option Ex. Open_form (’Stocks ‘,active,session).
when invoke the mulitiple forms with open form and call_form in the same
application, state whether the following are true/False
31. What are the ways to monitor
the performance of the report? - Use reports profile
executable statement. Use SQL trace facility.
32. If two groups are not linked in
the data model editor, What is the hierarchy between them? - Two group that is above are the left most rank higher than the
group that is to right or below it.
33. An open form can not be execute
the call_form procedure if you chain of called forms has been initiated by
another open form? - True
34. Explain about horizontal,
Vertical tool bar canvas views? - Tool bar canvas views
are used to create tool bars for individual windows. Horizontal tool bars are
display at the top of a window, just under its menu bar. Vertical Tool bars are
displayed along the left side of a window
35. What is the purpose of the
product order option in the column property sheet? - To specify the order of individual group evaluation in a cross
products.
36. What is the use of image_zoom
built-in? - To manipulate images
in image items.
37. How do you reference a
parameter indirectly? - To indirectly
reference a parameter use the NAME IN, COPY ‘built-ins to indirectly set and
reference the parameters value’ Example name_in (’capital parameter my param’),
Copy (’SURESH’,'Parameter my_param’)
DBA
Interview Questions - Part 5
March 17, 2006
1. What is a timer? - Timer is an “internal time clock†that you can programmatically create to perform an action each
time the times.
2. What are the two phases of
block coordination? - There are two phases
of block coordination: the clear phase and the population phase. During, the
clear phase, Oracle Forms navigates internally to the detail block and flushes
the obsolete detail records. During the population phase, Oracle Forms issues a
SELECT statement to repopulate the detail block with detail records associated
with the new master record. These operations are accomplished through the
execution of triggers.
3. What are Most Common types of
Complex master-detail relationships? - There are three most common types of complex master-detail
relationships: master with dependent details master with independent details
detail with two masters
4. What is a text list? - The text list style list item appears as a rectangular box which
displays the fixed number of values. When the text list contains values that
can not be displayed, a vertical scroll bar appears, allowing the operator to
view and select values that are not displayed.
5. What is term? - The term is terminal definition file that describes the terminal
form which you are using r20run.
6. What is use of term? - The term file which key is correspond to which oracle report
functions.
7. What is pop list? - The pop list style list item appears initially as a single field
(similar to a text item field). When the operator selects the list icon, a list
of available choices appears.
8. What is the maximum no of chars
the parameter can store? - The maximum no of
chars the parameter can store is only valid for char parameters, which can be
up to 64K. No parameters default to 23 Bytes and Date parameter default to 7
Bytes.
9. What are the default extensions
of the files created by library module? - The default file extensions indicate the library module type and
storage format .pll - pl/sql library module binary
10. What are the Coordination
Properties in a Master-Detail relationship? - The coordination properties are Deferred Auto-Query These
Properties determine when the population phase of block coordination should
occur.
11. How do you display console on a
window? - The console includes
the status line and message line, and is displayed at the bottom of the window
to which it is assigned. To specify that the console should be displayed, set
the console window form property to the name of any window in the form. To
include the console, set console window to Null.
12. What are the different
Parameter types? - Text ParametersData
Parameters
13. State any three mouse events
system variables? -
System.mouse_button_pressedSystem.mouse_button_shift
14. What are the types of
calculated columns available? - Summary, Formula,
Placeholder column.
15. Explain about stacked canvas
views? - Stacked canvas view is displayed in a
window on top of, or “stacked†on the content
canvas view assigned to that same window. Stacked canvas views obscure some part
of the underlying content canvas view, and or often shown and hidden
programmatically.
16. What are the built_ins used the
display the LOV? - Show_lov List_values
17. What is the difference between
SHOW_EDITOR and EDIT_TEXTITEM? - Show editor is the
generic built-in which accepts any editor name and takes some input string and
returns modified output string. Whereas the edit_textitem built-in needs the
input focus to be in the text item before the built-in is executed.
18. What are the built-ins that are
used to Attach an LOV programmatically to an item? - set_item_property get_item_property (by setting the LOV_NAME
property)
DBA
Interview Questions - Part 6
March 18, 2006
1. How do you call other Oracle
Products from Oracle Forms? - Run_product is a
built-in, Used to invoke one of the supported oracle tools products and
specifies the name of the document or module to be run. If the called product
is unavailable at the time of the call, Oracle Forms returns a message to the
operator.
2. What is the main diff. bet.
Reports 2.0 & Reports 2.5? - Report 2.5 is object
oriented.
3. What are the different file
extensions that are created by oracle reports? - Rep file and Rdf file.
4. What is strip sources generate
options? - Removes the source
code from the library file and generates a library files that contains only
pcode. The resulting file can be used for final deployment, but can not be
subsequently edited in the designer.ex. f45gen module=old_lib.pll
userid=scott/tiger strip_source YES output_file
5. What is the basic data
structure that is required for creating an LOV? - Record Group.
6. What is the Maximum allowed
length of Record group Column? - Record group column
names cannot exceed 30 characters.
7. Which parameter can be used to
set read level consistency across multiple queries? - Read only
8. What are the different types of
Record Groups? - Query Record
Groups NonQuery
Record Groups
State
9. From which designation is it
preferred to send the output to the printed? - Previewer
10. 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.
11. What are the different display
styles of list items? - Pop_list Text_list
Combo box
12. Which of the above methods is
the faster method? - performing the
calculation in the query is faster.
13. With which function of summary
item is the compute at options required? - percentage of total functions.
14. What are parameters? - Parameters provide a simple mechanism for defining and setting
the values of inputs that are required by a form at startup. Form parameters are
variables of type char, number, date that you define at design time.
15. What are the three types of
user exits available? - Oracle Precompiler
exits, Oracle call interface, NonOracle user exits.
16. 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
17. If the maximum record retrieved
property of the query is set to 10 then a summary value will be calculated? - Only for 10 records.
18. What are the two repeating
frame always associated with matrix object? - One down repeating frame below one across repeating frame.
19. What are the master-detail
triggers? -
On-Check_delete_master, On_clear_details, On_populate_details
20. What are the different objects
that you cannot copy or reference in object groups? - Objects of different modules Another object groups Individual
block dependent items Program units.
21. What is an OLE? - Object Linking & Embedding provides you with the capability
to integrate objects from many Windows applications into a single compound
document creating integrated applications enables you to use the features form.
22. Is it possible to modify an
external query in a report which contains it? - No.
23. Does a grouping done for
objects in the layout editor affect the grouping done in the data model editor? - No.
24. Can a repeating frame be
created without a data group as a base? - No
25. If a break order is set on a
column would it affect columns which are under the column? - No
26. Is it possible to set a filter
condition in a cross product group in matrix reports? - No
27. Do user parameters appear in
the data modal editor in 2.5? - No
28. Can you pass data parameters to
forms? - No
29. Is it possible to link two
groups inside a cross products after the cross products group has been created? - no
30. What are the different modals
of windows? - Modeless windows
Modal windows
31. What are modal windows? - Modal windows are usually used as dialogs, and have restricted
functionality compared to modeless windows. On some platforms for example
operators cannot resize, scroll or iconify a modal window.
DBA
Interview Questions - Part 7
March 19, 2006
1. 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
2. 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
3. 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
4. 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.
5. 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.
6. 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.
7. 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.
8. What is
system.coordination_operation? - It represents the
coordination causing event that occur on the master block in master-detail
relation.
9. 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.
10. 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.
11. What is a Text_io Package? - It allows you to read and write information to a file in the
file system.
12. What is forms_DDL? - Issues dynamic Sql statements at run time, including server side
pl/SQl and DDL
13. 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.
14. What are the different styles
of activation of ole Objects? - In place activation,
External activation
15. 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
16. 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.
17. Name of the functions used to
get/set canvas properties? - Get_view_property,
Set_view_property
18. What are the built-ins that are
used for setting the LOV properties at runtime? - get_lov_property set_lov_property
19. 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)
20. 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)
21. What are the built-in used for
getting cell values? -
Get_group_char_cell(function) Get_groupcell(function)
Get_group_number_cell(function)
22. What are the built-ins used for
Getting cell values? - GET_GROUP_CHAR_CELL
(function) GET_GROUPCELL(function) GET_GROUP_NUMBET_CELL(function)
23. A tleast how many set of data
must a data model have before a data model can be base on it? - Four
24. To execute row from being
displayed that still use column in the row which property can be used? - Format trigger.
DBA
Interview Questions - Part 8
March 20, 2006
1. 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
2. What is the remove on exit
property? - For a modeless
window, it determines whether oracle forms hides the window automatically when
the operators navigates to an item in the another window.
3. 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. Generally occurs only when
the operators modifies the first item in the record, and after the operator
attempts to navigate out of the item.
4. 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.
5. What are built-ins associated
with timers? - find_timer
create_timer delete_timer
6. What are the built-ins used for
finding object ID functions? - Find_group(function)
Find_column(function)
7. What are the built-ins used for
finding Object ID function? - FIND_GROUP(function)
FIND_COLUMN(function)
8. Any attempt to navigate
programmatically to disabled form in a call_form stack is allowed? - False
9. Use the Add_group_row procedure
to add a row to a static record group 1. true or false? - False
10. Use the add_group_column
function to add a column to record group that was created at a design time? - False
11. What are the various sub events
a mouse double click event involves? - What are the various sub events a mouse double click event
involves? - Double clicking the
mouse consists of the mouse down, mouse up, mouse click, mouse down & mouse
up events.
12. How can a break order be
created on a column in an existing group? - What are the various sub events a mouse double click event
involves? - By dragging the
column outside the group.
13. What is the use of place holder
column? - What are the various
sub events a mouse double click event involves? - A placeholder column is used to hold
calculated values at a specified place rather than allowing is to appear in the
actual row where it has to appear.
14. What is the use of hidden
column? - What are the various
sub events a mouse double click event involves? - A hidden column is used to when a
column has to embed into boilerplate text.
15. What is the use of break group? - What are the various sub events a mouse double click event
involves? - A break group is used
to display one record for one group ones. While multiple related records in
other group can be displayed.
16. What is an anchoring object
& what is its use? - What are the various
sub events a mouse double click event involves? - An anchoring object is a print
condition object which used to explicitly or implicitly anchor other objects to
itself.
17. What are the various sub events
a mouse double click event involves? - What are the various sub events a mouse double click event
involves? - Double clicking the
mouse consists of the mouse down, mouse up, mouse click, mouse down & mouse
up events.
18. What are the default parameter
that appear at run time in the parameter screen? - What are the various sub events a mouse double click event
involves? - Destype and Desname.
19. What are the built-ins used for
Creating and deleting groups? - CREATE-GROUP
(function) CREATE_GROUP_FROM_QUERY(function) DELETE_GROUP(procedure)
20. What are different types of
canvas views? - Content canvas views
Stacked canvas views Horizontal toolbar vertical toolbar.
21. What are the different types of
Delete details we can establish in Master-Details? - Cascade Isolate Non-isolate
22. What is relation between the
window and canvas views? - Canvas views are the
back ground objects on which you place the interface items (Text items), check
boxes, radio groups etc.,) and boilerplate objects (boxes, lines, images etc.,)
that operators interact with us they run your form . Each canvas views
displayed in a window.
23. What is a User_exit? - Calls the user exit named in the user_exit_string. Invokes a 3Gl
program by name which has been properly linked into your current oracle forms
executable.
24. How is it possible to select
generate a select set for the query in the query property sheet? - By using the tables/columns button and then specifying the table
and the column names.
25. How can values be passed
between precompiler exits & Oracle call interface? - By using the statement EXECIAFGET & EXECIAFPUT.
26. How can a square be drawn in
the layout editor of the report writer? - By using the rectangle tool while pressing the (Constraint) key.
27. How can a text file be attached
to a report while creating in the report writer? - By using the link file property in the layout boiler plate
property sheet.
28. How can I message to passed to
the user from reports? - By using SRW.MESSAGE
function.
29. How is possible to restrict the
user to a list of values while entering values for parameters? - By setting the Restrict To List property to true in the
parameter property sheet.
30. How can a button be used in a
report to give a drill down facility? - By setting the action associated with button to Execute pl/SQL
option and using the SRW.Run_report function.
31. How can a cross product be
created? - By selecting the
cross products tool and drawing a new group surrounding the base group of the
cross products.
DBA
Interview Questions - Part 9
March 21, 2006
1. What are different types of
images? - Boiler plate images,
Image Items
2. What is the difference between
boiler plat images and image items? - Boiler plate Images are static images (Either vector or bit map)
that you import from the file system or database to use a graphical elements in
your form, such as company logos and maps. Image items are special types of
interface controls that store and display either vector or bitmap images. Like
other items that store values, image items can be either base table items
(items that relate directly to database columns) or control items. The
definition of an image item is stored as part of the form module FMB and FMX
files, but no image file is actually associated with an image item until the
item is populate at run time.
3. What is bind reference and how
can it be created? - Bind reference are
used to replace the single value in sql, pl/sql statements a bind reference can
be created using a (:) before a column or a parameter name.
4. What are the triggers available
in the reports? - Before report, Before
form, After form , Between page, After report.
5. Give the sequence of execution
of the various report triggers? - Before form , After
form , Before report, Between page, After report.
6. Why is a Where clause faster
than a group filter or a format trigger? - Because in a where clause the condition is applied during data
retrieval, then after retrieving the data.
7. Why is it preferable to create
a fewer no. of queries in the data model? - Because for each query, report has to open a separate cursor and
has to rebind, execute and fetch data.
8. Where is the external query
executed at the client or the server? - At the server.
9. Where is a procedure return in
an external pl/SQL library executed at the client or at the server? - At the client.
10. What is coordination Event? - Any event that makes a different record in the master block the
current record is a coordination causing event.
11. What is the difference between
OLE Server & OLE Container? - An Ole server
application creates ole Objects that are embedded or linked in ole Containers
ex. Ole servers are ms_word & ms_excel. OLE containers provide a place to
store, display and manipulate objects that are created by ole server
applications. Ex. oracle forms is an example of an ole Container.
12. What is an object group? - An object group is a container for a group of objects; you
define an object group when you want to package related objects, so that you
copy or reference them in other modules.
13. What is an LOV? - An LOV is a scrollable popup window that provides the operator
with either a single or multi column selection list.
14. At what point of report
execution is the before Report trigger fired? - After the query is executed but before the report is executed
and the records are displayed.
15. What are the built -ins used
for Modifying a groups structure? - ADD-GROUP_COLUMN
(function) ADD_GROUP_ROW (procedure) DELETE_GROUP_ROW(procedure)
16. What is an user exit used for? - A way in which to pass control (and possibly arguments ) form
Oracle report to another Oracle products of 3 GL and then return control ( and
) back to Oracle reports.
17. What is the User-Named Editor? - A user named editor has the same text editing functionality as
the default editor, but, because it is a named object, you can specify editor
attributes such as windows display size, position, and title.
18. What are the Built-ins to
display the user-named editor? - A user named editor
can be displayed programmatically with the built in procedure SHOW-EDITOR,
EDIT_TETITEM independent of any particular text item.
19. What is a Static Record Group? - A static record group is not associated with a query, rather,
you define its structure and row values at design time, and they remain fixed at
runtime.
20. What is a record group? - A record group is an internal Oracle Forms that structure that
has a column/row framework similar to a database table. However, unlike
database tables, record groups are separate objects that belong to the form
module which they are defined.
21. How many number of columns a
record group can have? - A record group can
have an unlimited number of columns of type CHAR, LONG, NUMBER, or DATE
provided that the total number of column does not exceed 64K.
22. What is a Query Record Group? - A query record group is a record group that has an associated
SELECT statement. The columns in a query record group derive their default
names, data types, had lengths from the database columns referenced in the
SELECT statement. The records in query record group are the rows retrieved by
the query associated with that record group.
23. What is a Non Query Record
Group?
24. What is a property clause? - A property clause is a named object that contains a list of
properties and their settings. Once you create a property clause you can base
other object on it. An object based on a property can inherit the setting of
any property in the clause that makes sense for that object.
DBA
Interview Questions - Part 10
March 22, 2006
1. What is a physical page? What is a logical page? - A physical page is a size of a page. That is output by the
printer. The logical page is the size of one page of the actual report as seen
in the Previewer.
2. What does the term panel refer
to with regarda to pages? - A panel is the number
of physical pages needed to print one logical page.
3. What is a master detail
relationship? - A master detail
relationship is an association between two base table blocks- a master block
and a detail block. The relationship between the blocks reflects a primary key
to foreign key relationship between the tables on which the blocks are based.
4. What is a library? - A library is a collection of subprograms including user named
procedures, functions and packages.
5. How can a group in a cross
products be visually distinguished from a group that does not form a cross
product? - A group that forms
part of a cross product will have a thicker border.
6. What is the frame &
repeating frame? - A frame is a holder
for a group of fields. A repeating frame is used to display a set of records
when the number of records that are to displayed is not known before.
7. What is a combo box? - A combo box style list item combines the features found in list
and text item. Unlike the pop list or the text list style list items, the combo
box style list item will both display fixed values and accept one operator
entered value.
8. What are three panes that
appear in the run time pl/SQL interpreter? - Source pane, interpreter pane, navigator pane.
9. What are the two panes that
Appear in the design time pl/SQL interpreter? - Source pane, interpreter pane
10. What are the two ways by which
data can be generated for a parameters list of values? - Using static values, writing select statement.
11. What are the various methods of
performing a calculation in a report? -Perform the calculation in the SQL statements itself, use a
calculated / summary column in the data model.
12. What are the default extensions
of the files created by menu module? - .mmb, .mmx
13. What are the default extensions
of the files created by forms modules? - .fmb - form module binary .fmx - form module executable
14. To display the page number for
each page on a report, what would be the source & logical page number or
physical page number?
15. It is possible to use raw
devices as data files and what is the advantages over file system files? - Yes. The advantages over file system files. I/O will be improved
because Oracle is bypassing the kernel when writing to disk. Disk Corruption
will decrease.
16. What are disadvantages of
having raw devices? - We should depend on
export/import utility for backup/recovery (fully reliable) The tar command
cannot be used for physical file backup, instead we can use dd command which is
less flexible and has limited recoveries.
17. What is the significance of
having storage clause? - We can plan the
storage for a table as how much initial extents are required, how much can be
extended next, how much % should leave free for managing row updations etc.,
18. What is the use of INCTYPE
option in EXP command? - Type export should be
performed COMPLETE, CUMULATIVE, INCREMENTAL. List the sequence of events when a
large transaction that exceeds beyond its optimal value when an entry wraps and
causes the rollback segment to expand into a notion Completes. e. will be
written.
19. What is the use of FILE option
in IMP command? - The name of the file
from which import should be performed.
20. What is a Shared SQL pool? - The data dictionary cache is stored in an area in SGA called the
Shared SQL Pool. This will allow sharing of parsed SQL statements among
concurrent users.
21. What is hot backup and how it
can be taken? - Taking backup of
archive log files when database is open. For this the ARCHIVELOG mode should be
enabled. The following files need to be backed up. All data files. All Archive
log, redo log files. All control files.
22. List the Optional Flexible
Architecture (OFA) of Oracle database? How can we organize the tablespaces in
Oracle database to have maximum performance?
A. SYSTEM - Data
dictionary tables.
B. DATA - Standard
operational tables.
C. DATA2- Static tables
used for standard operations
D. INDEXES - Indexes for
Standard operational tables.
E. INDEXES1 - Indexes of
static tables used for standard operations.
F. TOOLS - Tools table.
G. TOOLS1 - Indexes for
tools table.
H. RBS - Standard
Operations Rollback Segments,
I.
RBS1,RBS2 - Additional/Special Rollback segments.
J. TEMP - Temporary
purpose tablespace
K. TEMP_USER - Temporary
tablespace for users.
L. USERS - User tablespace.
23. How to implement the multiple
control files for an existing database?
A. Shutdown the database
B. Copy one of the
existing control file to new location
C. Edit Config ora file by
adding new control filename
D. Restart the database.
24. What is advantage of having disk
shadowing/ Mirroring? - Shadow set of disks
save as a backup in the event of disk failure. In most Operating System if any
disk failure occurs it automatically switches over to a working disk. Improved
performance because most OS support volume shadowing can direct file I/O
request to use the shadow set of files instead of the main set of files. This
reduces I/O load on the main set of disks.
25. How will you force database to
use particular rollback segment? - SET TRANSACTION USE
ROLLBACK S
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