Oracle Interview Questions

• OracleExplain the difference between a hot backup and a cold backup and the benefits associated with each You have just had to restore from backup and do not have any control files. How would you go about bringing up this database?
• How do you switch from an init.ora file to a spfile?
• Explain the difference between a data block, an extent and a segment.
• Give two examples of how you might determine the structure of the table DEPT. Where would you look for errors from the database engine?
• Compare and contrast TRUNCATE and DELETE for a table.
• Give the reasoning behind using an index.
• Give the two types of tables involved in producing a star schema and the type of data they hold. . What type of index should you use on a fact table? .
• Give two examples of referential integrity constraints. A table is classified as a parent table and you want to drop and re-create it. How would you do this without affecting the children tables?
• Explain the difference between ARCHIVELOG mode and NOARCHIVELOG mode and the benefits and disadvantages to each.
• What command would you use to create a backup control file?
• Give the stages of instance startup to a usable state where normal users may access it. What column differentiates the V$ views to the GV$ views and how?
• How would you go about generating an EXPLAIN plan?
• How would you go about increasing the buffer cache hit ratio?
• Explain an ORA-01555
• Explain the difference between $ORACLE_HOME and $ORACLE_BASE.
• How would you determine the time zone under which a database was operating?
• Explain the use of setting GLOBAL_NAMES equal to TRUE.
• What command would you use to encrypt a PL/SQL application?
• Explain the difference between a FUNCTION, PROCEDURE and PACKAGE.
• Explain the use of table functions.
• Name three advisory statistics you can collect.
• Where in the Oracle directory tree structure are audit traces placed?
• Explain materialized views and how they are used.
• When a user process fails, what background process cleans up after it?
• What background process refreshes materialized views?
• How would you determine what sessions are connected and what resources they are waiting for?
• Describe what redo logs are.
• How would you force a log switch?
• Give two methods you could use to determine what DDL changes have been made.
• What does coalescing a tablespace do?
• What is the difference between a TEMPORARY tablespace and a PERMANENT tablespace?
• Name a tablespace automatically created when you create a database.
• When creating a user, what permissions must you grant to allow them to connect to the database? How do you add a data file to a tablespace?
• How do you resize a data file?
• What view would you use to look at the size of a data file?
• What view would you use to determine free space in a tablespace?
• How would you determine who has added a row to a table?
• How can you rebuild an index?
• Explain what partitioning is and what its benefit is.
• You have just compiled a PL/SQL package but got errors, how would you view the errors?
• How can you gather statistics on a table?
• How can you enable a trace for a session?
• What is the difference between the SQL*Loader and IMPORT utilities?
• Name two files used for network connection to a database