With well over a decade of Oracle experience from version 6 to 11g, I have had my share of interviewing prospective DBA employees in a range from Junior to Senior DBAs. Needless to say in this field, technical competence is the key to any new hire and early on I made the blunder of not asking the write questions during the interview. I am sure every senior person or manager has made this mistake and had to deal with either training the person from scratch or letting them go. Either of these options is not desirable in our fast past business world. So, I decided to write a couple articles which cover what I believe a Junior, Mid, and Senior Oracle DBA should know to fill their prospective positions.

In this article we will cover what a Mid Level DBA should know to be successful. If you have any comments or questions, please email me at larry.catt@relidb.com.

Questions:

1. Define the directory where Oracle developed scripts reside for the maintenance of an Oracle database and how would you call this directory from within the Oracle database?

2. Define the difference between, USER_, ALL_, and DBA_ data dictionary views and define the one column missing from USER_ which exists in both ALL_ and DBA_ views?

3. How would you find the number of invalid objects in an Oracle database and how would you resolve them?

4. Where are the network related files located on a standard Oracle installation and name two of the standard files you would find there?

5. Define the Oracle utility provided for backup and recovery of an Oracle database and the two options for storing information about backed up databases?

6. Define the Oracle utility used to manage an Oracle listener?

7. Define two UNIX layer system variables required for an Oracle database to operate properly?

8. Define the Oracle utility normally used to install CPU patches and where is this utility stored?

9. Name the Oracle package which allows you to schedule routine jobs within the Oracle database, just like CRON in UNIX or Scheduler in Windows?

10. Name the utility used to format perfstat report trace files?

Answers:

1. Define the directory where Oracle developed scripts reside for the maintenance of an Oracle database and how would you call this directory from within the Oracle database?

– The directory where Oracle stores the maintenance scripts is $ORACLE_HOME/rdbms/admin.
– The question mark represents the ORACLE_HOME within the database, thus you would call this directory with ‘?/rdbms/admin’. Another acceptable answer is ‘@?/rdbms/admin’.

2. Define the difference between, USER_, ALL_, and DBA_ data dictionary views and define the one column missing from USER_ which exists in both ALL_ and DBA_ views?

– USER_ – These views only contain definition of objects which you own.
– ALL_ – These views contain definitions of all objects which you have access to.
– DBA_ – These views contain definitions of all objects in the database, even if you do not have access to them.

– The USER_ views do not contain a column named OWNER, by definition of the view you are the owner.

3. How would you find the number of invalid objects in an Oracle database and how would you resolve them?

– By using the data dictionary view DBA_OBJECTS with the statement “select count(*) from dba_objects where status=’INVALID’;”
– You would use the Oracle script, “UTLRP.SQL” located in directory $ORACLE_HOME/rdbms/admin.

4. Where are the network related files located on a standard Oracle installation and name two of the standard files you would find there?

– In a standard Oracle installation the network files are located under “$ORACLE_HOME/network/admin”.
– Files located in this directory are: “LISTENER.ORA”, “TNSNAMES.ORA”, or “SQLNET.ORA”.

5. Define the Oracle utility provided for backup and recovery of an Oracle database and the two options for storing information about backed up databases?

– RMAN (Recovery Manager)
– The two methods for storing information about backed up database are: the controlfile or Recovery Catalog.

6. Define the Oracle utility used to manage an Oracle listener?

– LSNRCTL (LISTENER CONTROL)

7. Define two UNIX layer system variables required for an Oracle database to operate properly?

– $ORACLE_HOME – defines the directory where the Oracle binaries are installed.
– $ORACLE_SID – defines the instance name used to access a database.

8. Define the Oracle utility normally used to install CPU patches and where is this utility stored?

– “opatch” is the utility which is used to install CPU patches.
– The “opatch” utility is located in the directory “$ORACLE_HOME/OPatch”. NOTE: “opatch” is not a valid answer in a standard Oracle installation the directory has a capital O and P.

9. Name the Oracle package which allows you to schedule routine jobs within the Oracle database, just like CRON in UNIX or Scheduler in Windows?

– DBMS_JOBS – This answer is valid for all versions of Oracle.
– DBMS_SCHEDULER – This answer is only valid for Oracle 10g or higher.

10. Name the utility used to format perfstat report trace files?

– TKPROF

Larry J. Catt, OCP 9i, 10g
oracle@allcompute.com
www.allcompute.com