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• Deepak Thapa

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Oracle Database Questions and Answers – Databases and Instances This set of Oracle Database Multiple Choice Questions & Answers (MCQs) focuses on “Databases and Instances”. 1. The Oracle environment of database is called as ___________ a) Database Schema b) Database Instances c) Data Structure d) All of the Mentioned View Answer Answer: b Explanation: A database instance is a set of memory structures that manage database files. 2. Which is the smallest unit of storage in an Oracle database? a) Data Block b) Segment c) Extent d) Data File View Answer Answer: a Explanation: The logical units of database space allocation are data blocks. 3. Collection of information stored in database at particular instance of time is called as ____________. a) Instance of Database b) Objects in Databases c) Data structure d) Database Schema View Answer Answer: a Explanation: Oracle work on the instance basis, whatever the operation related to Oracle is only on instance level. 4. Oracle database’s design is also called as_____? a) Database Abstraction b) Database Instance c) Database Schema d) None of the Mentioned View Answer Answer: c Explanation: Oracle database’s design is done on the schema level. advertisements 5. What are the valid Oracle database schemas? a) Logical Schema b) Physical Schema c) Logical and Physical Schema d) None of the Mentioned

View Answer Answer: c Explanation: Oracle databases has two schema level logical and physical. 6. What do the schema objects comprise of? a) Table b) Index c) Cluster d) All of the Mentioned View Answer Answer: d Explanation: Oracle database schema consists of Table, Index, Cluster. 7. Map entities, attributes and relations in Oracle is represented by___________ a) Conceptual Schema b) Logical Schema c) Physical Schema d) All of the Mentioned View Answer Answer: b Explanation: Logical schema model may have many-to-many relationships and also have objects like table, view, procedure etc. 8. Modification schema of oracle database in one level without affecting the schema in high level is called as _______ a) Data Migration b) Data Isolation c) Data Independence d) Data Abstraction View Answer Answer: c Explanation: Data Independence means changing internal level does not affect conceptual level. 9. A _______________ is used to logically group data together a) Database b) Tablespace c) Datafiles d) Object View Answer Answer: b Explanation: Oracle database consists of one or more logical storage units called tablespaces. advertisements 10. A _____________ is a set of tables physically stored together as one table that shares a common column a) Index b) Object c) Datafiles

d) Cluster View Answer Answer: d Explanation: Cluster is a schema object that contains data from one or more tables, all of which have one or more columns in common.