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    Maxwell Miranda
    Oracle DBA Consultant.
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    • Can't access database after power outage
      I could access the database before the power outage. From what I've read, it is a problem with the environment variables, but they are correct. Not sure what else to add. C:\Documents and Settings\konoca>sqlplus / as sysdba SQL*Plus: Release - Production on Wed Feb 21 09:17:08 2018 Copyright (c) 1982, 2005, Oracle. All rights reserved. ERR […]
    • Problems with RESET DATABASE
      Recently I wanted to do RESET DATABASE. Oracle documentation suggests the following commands connect target / startup force nomount reset database to incarnation 2 run { set until time "date time" restore controlfile from autobackup alter database mount restore database recover database } alter database open resetlogs In this view my db has given e […]
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Database character set in oracle

The database character set in oracle determines the set of characters can be stored in the database. It is also used to determine the character set to be used for object identifiers.

The database character set information is stored in the data dictionary tables named SYS.PROPS$.

You can get the character set used in the database by SYS.PROPS$ table or any other views (like database_properties/ nls_database_parameters) exist in the database. The parameter NLS_CHARACTERSET value contains the database character set name. Get it from,

SQL> select value$ from sys.props$ where name=’NLS_CHARACTERSET’;


SQL> select property_value from database_properties where property_name=


SQL> select value from nls_database_parameters where parameter=’NLS_CHARACTERSET’;



What is Oracle Instant Client?

•Instant Client allows you to run your applications
without installing the standard Oracle client or
having an ORACLE_HOME.
•While using significantly less disk space than
•SQL*Plus can be used with Instant Client

Some oracle DBA questions – Part 1

What are things which play major role in designing the backup strategy?
What are RTO, MTBF, and MTTR?
What are the various tape backup solutions available in the market?
What is RAID? What is RAID0? What is RAID1? What is RAID 10?
What is the difference between physical and logical backups?
What is hot backup and what is cold backup?
When do you recommend hot backup? What are the pre-reqs?
How do you generate the begin backup script?
Give me the steps for recovering the full database from cold backup?
Give me the steps for TIME based recovery from the full database from hot backup. ?
Give me the steps for SCN based recovery from the full database from hot backup. ?
Give me the steps for CANCEL based recovery from the full database from hot backup. ?
Give me the steps for recovery with missing archived redo logs?
Give me the steps for recovery with missing online redo logs?
Give me the steps for recovery of missing data file?
Give me the steps for physical standby database creation?
What is db_recovery_file_dest ? When do you need to set this value ?
Give me the steps to perform the point in time recovery with a backup which is taken before the resetlogs of the db ?
Tell me about the steps required to enable the RMAN backup for a target database ?
What is the difference between obsolete RMAN backups and expired RMAN backups ?
What is recovery catalog ? Why do you need this ?
How do you install the RMAN recovery catalog ?
Can you skip specific tables when using RMAN DUPLICATE feature ?
How do you clone the database using RMAN software ? Give me the brief steps ? when do you use crosscheck command ?
How do you setup the RMAN tape backups ?
How do you identify the expired,active,obsolete backups ? Which RMAN command you use ?
What is channel ? How do you enable the parallel backups with RMAN ?
What is auxiliary channel in RMAN? When do you need this ?
How do you identify what are the all the target databases that are being backed-up with RMAN database ?
Give me some of the RMAN catalog view names which contains the catalog information ?
What is oracle wallet ? Tell me about the encryption options available with RMAN ?
List advantages of RMAN backups compare to traditional hot backups ?
How do you identify the block corruption in RMAN database ? How do you fix this ?
How do you verify the integrity of the image copy in RMAN environment ?
How do you enable the encryption for RMAN backups ?
What is backup set ?
What is the difference between cumulative incremental and differential incremental backups ?
How do you enable the autobackup for the controlfile using RMAN ?
What is configure command ? When do you use this ?
Give me the steps for setting up the physical stand by database with RMAN ?
Give me the steps for changing the DBID in a cloned environment ?
What is the significance of incarnation and DBID in the RMAN backups ?