Oracle Interview Questions and Answers
Question - 41 : - How are the index updates?
Answer - 41 : - Indexes are automatically maintained and used by Oracle. Changes to table data are automatically incorporated into all relevant indexes.
Question - 42 : - What is a Tablespace?
Answer - 42 : - A database is divided into Logical Storage Unit called tablespace. A tablespace is used to grouped related logical structures together
Question - 43 : - What is Rollback Segment ?
Answer - 43 : - A Database contains one or more Rollback Segments to temporarily store "undo" information.
Question - 44 : - What are the Characteristics of Data Files ?
Answer - 44 : - A data file can be associated with only one database. Once created a data file can't change size. One or more data files form a logical unit of database storage called a tablespace.
Question - 45 : - How to define Data Block size ?
Answer - 45 : - A data block size is specified for each ORACLE database when the database is created. A database users and allocated free database space in ORACLE data blocks. Block size is specified in INIT.ORA file and can’t be changed latter.
Question - 46 : - What does a Control file Contain ?
Answer - 46 : - A Control file records the physical structure of the database. It contains the following information.
Database Name
Names and locations of a database's files and redolog files.
Time stamp of database creation.
Question - 47 : - What is difference between UNIQUE constraint and PRIMARY KEY constraint ?
Answer - 47 : - A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls.
Question - 48 : - What is Index Cluster ?
Answer - 48 : - A Cluster with an index on the Cluster Key
Question - 49 : - When does a Transaction end ?
Answer - 49 : - When it is committed or Rollbacked.
Question - 50 : - What is the effect of setting the value "ALL_ROWS" for OPTIMIZER_GOAL parameter of the ALTER SESSION command ? What are the factors that affect OPTIMIZER in choosing an Optimization approach ?
Answer - 50 : - Answer The OPTIMIZER_MODE initialization parameter Statistics in the Data Dictionary the OPTIMIZER_GOAL parameter of the ALTER SESSION command hints in the statement.