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Tuesday 29 January 2013

Oracle InterViewQusetions 11-15

11. what is null value?
Null Value is neither zero nor it is a blank space. It is some unknown value which occupies 4 bytes of space of memory in SQL.

12. Define transaction?
A transaction is a sequence of SQL statements that Oracle Database treats as a single unit.

13. what is the difference between sql&oracle?
SQL is Stuctured Query Language.Oracle is a Database.SQL is used to write queries against Oracle DB.

14. What are different Oracle database objects?
TABLES
VIEWS
INDEXES
SYNONYMS
SEQUENCES
TABLESPACES

15. What is hash cluster?
A row is stored in a hash cluster based on the result of applying a hash function to the row's cluster key value. All rows with the same hash key value are stores together on disk.

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