Tag: databases

RMAN prompt

SQLPLUS prompt

Oracle Enterprise Manager 11g (OEM)

DRA prompt

rman > list failure;

rman > report failure;

rman > diagnose failure;

rman > advise failure;

rman > repair failure preview;

rman > repair failure;

database

datafile

tracefile

spfile

controlfilecopy

flash recovery area

ZLIB compression gives better compression ratio in comparison to BZIP2 compression

BZIP2 compression gives better compression ratio in comparison to ZLIB compression

ZLIB compression consumes much lesser CPU in comparison to BZIP2 compression

BZIP2 compression consumes much lesser CPU in comparison to ZLIB compression

ZLIB compression comes with additional licensing cost. BZIP2 compression comes with no additional cost

BZIP2 compression comes with additional licensing cost. ZLIB compression comes with no additional cost

rman > configure compression algorithm ‘zlib’;

rman > configure compression algorithm ‘zlib11g’;

rman > set compression algorithm ‘zlib’;

rman > set compression algorithm ‘zlib11g’;

Scenario 1: Backup 2 datafiles each of 20 GB datafile using 4 RMAN channels. Use the default setting for all RMAN channels

Scenario 2: Backup 2 datafiles each of 20 GB datafile using 4 RMAN channels. Each channel backs up 2 datafiles at the same time with “parallel=2”

Scenario 3: Backup 2 datafiles each of 20 GB size using 4 RMAN channels. Each channel backs up data with “section size=5GB"

Scenario 4: Backup 2 datafiles each of 20 GB datafile using 4 RMAN channels. Each channel backs up 2 datafiles at the same time with “parallel backups=2”

You can use group functions in any clause of a select statement

You can use group functions only in the column list of the SELECT statement by grouping on the single row columns

You can pass column names, expressions, constants or functions as parameters to a group function

You cannot group the rows of a table by more than one column while using group functions

SELECT SUBSTR('Hello',) FROM dual;

SELECT INITCAP(TRIM('Hello World',1,1)) FROM dual;

SELECT LOWER(SUBSTR('Hello World',1,1)) FROM dual;

SELECT LOWER(SUBSTR('Hello World',2,1)) FROM dual;

SELECT LOWER(TRIM('H' FROM 'Hello World')) FROM dual;

True

False

Indexes are only used in special cases

Indexes are used to make table storage more efficient

Indexes rarely make a difference in SQL performance

Indexes exist solely to improve query speed.