PROGRAMMATIC CONSTRUCTS
110. What are the different types of PL/SQL program units that can be defined and stored in ORACLE
database ?
Procedures and Functions,Packages and Database Triggers.
111. What is a Procedure ?
A Procedure consist of a set of SQL and PL/SQL statements that are grouped together as a unit to solve a
specific problem or perform a set of related tasks.
112. What is difference between Procedures and Functions ?
A Function returns a value to the caller where as a Procedure does not.
113. What is a Package ?
A Package is a collection of related procedures, functions, variables and other package constructs together
as a unit in the database.
114. What are the advantages of having a Package ?
Increased functionality (for example,global package variables can be declared and used by any
proecdure in the package) and performance (for example all objects of the package are parsed compiled,
and loaded into memory once)
115. What is Database Trigger ?
A Database Trigger is procedure (set of SQL and PL/SQL statements) that is automatically executed as a
result of an insert in,update to, or delete from a table.
116. What are the uses of Database Trigger ?
Database triggers can be used to automatic data generation, audit data modifications, enforce complex
Integrity constraints, and customize complex security authorizations.
117. What are the differences between Database Trigger and Integrity constraints ?
A declarative integrity constraint is a statement about the database that is always true. A constraint
applies to existing data in the table and any statement that manipulates the table.
A trigger does not apply to data loaded before the definition of the trigger, therefore, it does not
guarantee all data in a table conforms to the rules established by an associated trigger.
A trigger can be used to enforce transitional constraints where as a declarative integrity constraint
cannot be used.
DATABASE SECURITY
118. What are Roles ?
Roles are named groups of related privileges that are granted to users or other roles.
119. 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.
120. How to prevent unauthorized use of privileges granted to a Role ?
By creating a Role with a password.
121. What is default tablespace ?
The Tablespace to contain schema objects created without specifying a tablespace name.
122. What is Tablespace Quota ?
The collective amount of disk space available to the objects in a schema on a particular tablespace.
123. What is a profile ?
Each database user is assigned a Profile that specifies limitations on various system resources available
to the user.
124. 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 amout 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.
125. What is Auditing ?
Monitoring of user access to aid in the investigation of database use.
126. What are the different Levels of Auditing ?
Statement Auditing, Privilege Auditing and Object Auditing.
127. What is Statement Auditing ?
Statement auditing is the auditing of the powerful system privileges without regard to specifically named
objects.
128. What is Privilege Auditing ?
Privilege auditing is the auditing of the use of powerful system privileges without regard to specifically named
objects.
129. What is Object Auditing ?
Object auditing is the auditing of accesses to specific schema objects without regard to user.
DISTRIBUTED PROCESSING AND DISTRIBUTED DATABASES
130. 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.
131. 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.
132. 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.
133. What is the mechanism provided by ORACLE for table replication ?
Snapshots and SNAPSHOT LOGs
134. 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.
135. 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.
136. 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.
DATABASE OPERATION, BACKUP AND RECOVERY
137. What are the steps involved in Database Startup ?
Start an instance, Mount the Database and Open the Database.
138. What are the steps involved in Database Shutdown ?
Close the Database, Dismount the Database and Shutdown the Instance.
139. 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.
140. 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.
141. 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.
142. Can Full Backup be performed when the database is open ?
No.
143. 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.
144.WhatisOn-lineRedoLog?
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.
145. 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.
146. What is Archived Redo Log ?
Archived Redo Log consists of Redo Log files that have archived before being reused.
147. 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.
148. 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.
149. What are the steps involved in Instance Recovery ?
R_olling 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.
Data Base Administration
Introduction to DBA
1. 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.
2. What is Parallel Server ?
Multiple instances accessing the same database (Only In Multi-CPU environments)
3. What is a Schema ?
The set of objects owned by user account is called the schema.
4. 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
comman (Ver 7.0)
5. What is clusters ?
Group of tables physically stored together because they share common columns and are often used
together is called Cluster.
6. 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.
7. 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
8. What is a deadlock ? Explain .
Two processes wating 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.
MEMORY MANAGEMENT
9. What is SGA ? How it is different from Ver 6.0 and Ver 7.0 ?
The System Global Area in a Oracle database is the area in memory to facilitates the transfer of
information between users. It holds the most recently requested structural information between users. It
holds the most recently requested structural information about the database.
The structure is Database buffers, Dictionary cache, Redo Log Buffer and Shared SQL pool (ver 7.0 only)
area.
10. 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.
11. What is mean by Program Global Area (PGA) ?
It is area in memory that is used by a Single Oracle User Process.
12. What is a data segment ?
Data segment are the physical areas within a database block in which the data associated with tables and
clusters are stored.
13. What are the factors causing the reparsing of SQL statements in SGA?
Due to insufficient Shared SQL pool size.
Monitor the ratio of the reloads takes place while executing SQL statements. If the ratio is
greater than 1 then increase the SHARED_POOL_SIZE.
LOGICAL & PHYSICAL ARCHITECTURE OF DATABASE.
14. What is Database Buffers ?
Database buffers are cache in the SGA used to hold the data blocks that are read from the data segments
in the database such as tables, indexes and clusters DB_BLOCK_BUFFERS parameter in INIT.ORA decides the
size.
15. What is dictionary cache ?
Dictionary cache is information about the databse objects stored in a data dictionary table.
16. What is meant by recursive hints ?
Number of times processes repeatedly query the dictionary table is called recursive hints. It is due to the
data dictionary cache is too small. By increasing the SHARED_POOL_SIZE parameter we can optimize the
size of Data Dictionary Cache.
17. What is meant by redo log buffer ?
Change made to entries are written to the on-line redo log files. So that they can be used in roll forward
operations during database recoveries. Before writing them into the redo log files, they will first brought to
redo log buffers in SGA and LGWR will write into files frequently.
LOG_BUFFER parameter will decide the size.
18. How will you swap objects into a different table space for an existing database ?
Export the user
Perform import using the command imp system/manager file=export.dmp indexfile=newrite.sql. This will
create all definitions into newfile.sql.
Drop necessary objects.
Run the script newfile.sql after altering the tablespaces.
Import from the backup for the necessary objects.
19. List the Optional Flexible Architecture (OFA) of Oracle database ? or How can we organise the
tablespaces in Oracle database to have maximum performance ?
SYSTEM - Data dictionary tables.
DATA - Standard operational tables.
DATA2- Static tables used for standard operations
INDEXES - Indexes for Standard operational tables.
INDEXES1 - Indexes of static tables used for standard operations.
TOOLS - Tools table.
TOOLS1 - Indexes for tools table.
RBS - Standard Operations Rollback Segments,
RBS1,RBS2 - Additional/Special Rollback segments.
TEMP - Temporary purpose tablespace
TEMP_USER - Temporary tablespace for users.
USERS - User tablespace.
20. How will you force database to use particular rollback segment ?
SET TRANSACTION USE ROLLBACK SEGMENT rbs_name.
21. What is meant by free extent ?
A free extent is a collection of continuous free blocks in tablespace. When a segment is dropped its extents
are reallocated and are marked as free.
22. How free extents are managed in Ver 6.0 and Ver 7.0 ?
Free extents cannot be merged together in Ver 6.0.
Free extents are periodically coalesces with the neighboring free extent in
Ver 7.0
23.Which parameter in Storage clause will reduce no. of rows per block?
PCTFREE parameter
Row size also reduces no of rows per block.
24. 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.,
25. How does Space allocation table place within a block ?
Each block contains entries as follows
Fixied block header
Variable block header
Row Header,row date (multiple rows may exists)
PCTEREE (% of free space for row updation in future)
26. What is the role of PCTFREE parameter is Storage clause ?
This is used to reserve certain amount of space in a block for expansion of rows.
27. What is the OPTIMAL parameter ?
It is used to set the optimal length of a rollback segment.
28. What is the functionality of SYSTEM table space ?
To manage the database level transactions such as modifications of the data dictionary table that record
information about the free space usage.
29. How will you create multiple rollback segments in a database ?
Create a database which implicitly creates a SYSTEM Rollback Segment in a SYSTEM tablespace.
Create a Second Rollback Segment name R0 in the SYSTEM tablespace.
Make new rollback segment available (After shutdown, modify init.ora file and Start database)
Create other tablespaces (RBS) for rollback segments.
Deactivate Rollback Segment R0 and activate the newly created rollback segments.
30. How the space utilisation takes place within rollback segments ?
It will try to fit the transaction in a cyclic fashion to all existing extents. Once it found an extent is in use
then it forced to acquire a new extent (No. of extents is based on the optimal size)
31. Why query fails sometimes ?
Rollback segment dynamically extent to handle larger transactions entry loads.
A single transaction may wipeout all avaliable free space in the Rollback Segment Tablespace. This prevents
other user using Rollback segments.
32. How will you monitor the space allocation ?
By quering DBA_SEGMENT table/view.
33. How will you monitor rollback segment status ?
Querying the DBA_ROLLBACK_SEGS view
IN USE - Rollback Segment is on-line.
AVAILABLE - Rollback Segment available but not on-line.
OFF-LINE - Rollback Segment off-line
INVALID - Rollback Segment Dropped.
NEEDS RECOVERY - Contains data but need recovery or corupted.
PARTLY AVAILABLE - Contains data from an unresolved transaction involving a distributed database.
34. 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 another extend.
Transaction Begins.
An entry is made in the RES header for new transactions entry
Transaction acquires blocks in an extent of RBS
The entry attempts to wrap into second extent. None is available, so that the RBS must extent.
The RBS checks to see if it is part of its OPTIMAL size.
RBS chooses its oldest inactive segment.
Oldest inactive segment is eliminated.
RBS extents
The Data dictionary table for space management are updated.
Transaction Completes.
35. How can we plan storage for very large tables ?
Limit the number of extents in the table
Separate Table from its indexes.
Allocate Sufficient temporary storage.
36. How will you estimate the space required by a non-clustered tables?
Calculate the total header size
Calculate the available dataspace per data block
Calculate the combined column lengths of the average row
Calculate the total average row size.
Calculate the average number rows that can fit in a block
Calculate the number of blocks and bytes required for the table.
After arriving the calculation, add 10 % additional space to calculate the initial extent size for a working table.
37. 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 bye-passing the kernnel which writing into disk.
Disk Corruption will be very less.
38. What is a Control file ?
Database's overall physical architecture is maintained in a file called control file. It will be used to
maintain internal consistency and guide recovery operations. Multiple copies of control files are advisable.
39. How to implement the multiple control files for an existing database ?
Shutdown the databse
Copy one of the existing control file to new location
Edit Config ora file by adding new control file.name
Restart the database.
40. What is meant by Redo Log file mirrorring ? How it can be achieved?
Process of having a copy of redo log files is called mirroring.
This can be achieved by creating group of log files together, so that LGWR will automatically writes them to
all the members of the current on-line redo log group. If any one group fails then database automatically
switch over to next group. It degrades performance.
41. 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 switchover to place of failed 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.
42. What is use of Rollback Segments In Database ?
They allow the database to maintain read consistency between multiple transactions.
43. What is a Rollback segment entry ?
It is the set of before image data blocks that contain rows that are modified by a transaction.
Each Rollback Segment entry must be completed within one rollback segment.
A single rollback segment can have multiple rollback segment entries.
44. What is hit ratio ?
It is a measure of well the data cache buffer is handling requests for data.
Hit Ratio = (Logical Reads - Physical Reads - Hits Misses)/ Logical Reads.
45. When will be a segment released ?
When Segment is dropped.
When Shrink (RBS only)
When truncated (TRUNCATE used with drop storage option)
46. What are disadvanteges 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.
47. List the factors that can affect the accuracy of the estimations ?
The space used transaction entries and deleted records does not become free immediately after completion
due to delayed cleanout.
Trailling nulls and length bytes are not stored.
Inserts of, updates to and deletes of rows as well as columns larger than a single datablock, can cause
fragmentation an chained row pieces.
DATABASE SECURITY & ADMINISTRATION
48. 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.
49. 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.
50. What are the dictionary tables used to monitor a database spaces ?
DBA_FREE_SPACE
DBA_SEGMENTS
DBA_DATA_FILES.
51. 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 Oralce license agreement
Controlling and monitoring user access to the database.
Monitoring and optimising 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.
52. 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 basetables 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.
54. What are the database administrators utilities avaliable ?
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.
55. 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.
56. 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.
57. 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 provies to roles.
Assign each role to group of users. This will simplify the job of assigning privileges to individual users.
58. What are the steps to switch a database's archiving mode between NO ARCHIVELOG and ARCHIVELOG
mode ?
1. Shutdown the database instance.
2. Backup the databse
3. Perform any operating system specific steps (optional)
4. Start up a new instance and mount but do not open the databse.
5. Switch the databse's archiving mode.
59. 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 databse.
60. 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 paded, %s - Log
sequence number not padded. %T - Thread number lef-zero-paded and %t - Thread number not
padded). The file name created is arch 0001 are if %S is used.
LOG_ARCHIVE_DEST = path.
61. What is the use of ANALYZE command ?
To perform one of these function on an index,table, or cluster:
- to collect statisties 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 of the table or cluster.
MANAGING DISTRIBUTED DATABASES.
62. How can we reduce the network traffic ?
- Replictaion of data in distributed environment.
- Using snapshots to replicate data.
- Using remote procedure calls.
63. 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.
64. What are the various type of snapshots ?
Simple and Complex.
65. Differentiate simple and complex, snapshots ?
- A simple snapshot is based on a query that does not contains GROUP BY clauses, CONNECT BY clauses,
JOINs, sub-query or snashot of operations.
- A complex snapshots contain atleast any one of the above.
66. What dynamic data replication ?
Updating or Inserting records in remote database through database triggers. It may fail if remote database
is having any problem.
67. How can you Enforce Refrencial 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.
68. What are the options available to refresh snapshots ?
COMPLETE - Tables are completly regenerated using the snapshot's 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.
69. 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.
70. 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).
72. 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.
MANAGING BACKUP & RECOVERY
73. What are the different methods of backing up oracle database ?
- Logical Backups
- Cold Backups
- Hot Backups (Archive log)
74. What is a logical backup ?
Logical backup involves reading a set of databse records and writing them into a file. Export utility is used
for taking backup and Import utility is used to recover from backup.
75. What is cold backup ? What are the elements of it ?
Cold backup is taking backup of all physical files after normal shutdown of database. We need to take.
- All Data files.
- All Control files.
- All on-line redo log files.
- The init.ora file (Optional)
76. What are the different kind of export backups ?
Full back - Complete database
Incremental - Only affected tables from last incremental date/full backup date.
Cumulative backup - Only affected table from the last cumulative date/full backup date.
77. 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.
78. What is the use of FILE option in EXP command ?
To give the export file name.
79. What is the use of COMPRESS option in EXP command ?
Flag to indicate whether export should compress fragmented segments into single extents.
80. What is the use of GRANT option in EXP command ?
A flag to indicate whether grants on databse objects will be exported or not. Value is 'Y' or 'N'.
81. What is the use of INDEXES option in EXP command ?
A flag to indicate whether indexes on tables will be exported.
82. What is the use of ROWS option in EXP command ?
Flag to indicate whether table rows should be exported. If 'N' only DDL statements for the databse objects
will be created.
83. What is the use of CONSTRAINTS option in EXP command ?
A flag to indicate whether constraints on table need to be exported.
84. What is the use of FULL option in EXP command ?
A flag to indicate whether full databse export should be performed.
85. What is the use of OWNER option in EXP command ?
List of table accounts should be exported.
86. What is the use of TABLES option in EXP command ?
List of tables should be exported.
87. What is the use of RECORD LENGTH option in EXP command ?
Record length in bytes.
88. What is the use of INCTYPE option in EXP command ?
Type export should be performed COMPLETE,CUMULATIVE,INCREMENTAL.
89. What is the use of RECORD option in EXP command ?
For Incremental exports, the flag indirects whether a record will be stores data dictionary tables recording
the export.
90. What is the use of PARFILE option in EXP command ?
Name of the parameter file to be passed for export.
91. What is the use of PARFILE option in EXP command ?
Name of the parameter file to be passed for export.
92. What is the use of ANALYSE ( Ver 7) option in EXP command ?
A flag to indicate whether statistical information about the exported objects should be written to export
dump file.
93. What is the use of CONSISTENT (Ver 7) option in EXP command ?
A flag to indicate whether a read consistent version of all the exported objects should be maintained.
94. What is use of LOG (Ver 7) option in EXP command ?
The name of the file which log of the export will be written.
95.What is the use of FILE option in IMP command ?
The name of the file from which import should be performed.
96. What is the use of SHOW option in IMP command ?
A flag to indicate whether file content should be displayed or not.
97. What is the use of IGNORE option in IMP command ?
A flag to indicate whether the import should ignore errors encounter when issuing CREATE commands.
98. What is the use of GRANT option in IMP command ?
A flag to indicate whether grants on database objects will be imported.
99. What is the use of INDEXES option in IMP command ?
A flag to indicate whether import should import index on tables or not.
100. What is the use of ROWS option in IMP command ?
A flag to indicate whether rows should be imported. If this is set to 'N' then only DDL for database objects
will be exectued.
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