Oracle Interview Questions and Answers
Question - 171 : - What are the different file extensions that are created by oracle reports?
Answer - 171 : - Rep file and Rdf file.
Question - 172 : - What is strip sources generate options?
Answer - 172 : - 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
Question - 173 : - How does one put a database into ARCHIVELOG mode?
Answer - 173 : - The main reason for running in archivelog mode is that one can provide 24-hour availability and guarantee complete data recoverability. It is also necessary to enable ARCHIVELOG mode before one can start to use on-line database backups. To enable ARCHIVELOG mode, simply change your database startup command script, and bounce the database:
SQLPLUS> connect sys as sysdba
SQLPLUS> startup mount exclusive;
SQLPLUS> alter database archivelog;
SQLPLUS> archive log start;
SQLPLUS> alter database open;
NOTE1: Remember to take a baseline database backup right after enabling archivelog mode. Without it one would not be able to recover. Also, implement an archivelog backup to prevent the archive log directory from filling-up.
NOTE2: ARCHIVELOG mode was introduced with Oracle V6, and is essential for database point-in-time recovery. Archiving can be used in combination with on-line and off-line database backups.
NOTE3: You may want to set the following INIT.ORA parameters when enabling ARCHIVELOG mode: log_archive_start=TRUE, log_archive_dest=... and log_archive_format=...
NOTE4: You can change the archive log destination of a database on-line with the ARCHIVE LOG START TO 'directory'; statement. This statement is often used to switch archiving between a set of directories.
NOTE5: When running Oracle Real Application Server (RAC), you need to shut down all nodes before changing the database to ARCHIVELOG mode.
Question - 174 : - What is the basic data structure that is required for creating an LOV?
Answer - 174 : - Record Group.
Question - 175 : - How does one backup archived log files?
Answer - 175 : - One can backup archived log files using RMAN or any operating system backup utility. Remember to delete files after backing them up to prevent the archive log directory from filling up. If the archive log directory becomes full, your database will hang! Look at this simple RMAN backup script:
RMAN> run {
2> allocate channel dev1 type disk;
3> backup
4> format '/app/oracle/arch_backup/log_t%t_s%s_p%p'
5> (archivelog all delete input);
6> release channel dev1;
7> }
Question - 176 : - Does Oracle write to data files in begin/hot backup mode?
Answer - 176 : - Oracle will stop updating file headers, but will continue to write data to the database files even if a tablespace is in backup mode.
In backup mode, Oracle will write out complete changed blocks to the redo log files. Normally only deltas (changes) are logged to the redo logs. This is done to enable reconstruction of a block if only half of it was backed up (split blocks). Because of this, one should notice increased log activity and archiving during on-line backups.
Question - 177 : - What is the Maximum allowed length of Record group Column?
Answer - 177 : - Record group column names cannot exceed 30 characters.
Question - 178 : - Which parameter can be used to set read level consistency across multiple queries?
Answer - 178 : - Read only
Question - 179 : - What are the different types of Record Groups?
Answer - 179 : - Query Record Groups
NonQuery Record Groups
State Record Groups
Question - 180 : - From which designation is it preferred to send the output to the printed?
Answer - 180 : - Previewer