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How would you go about increasing the buffer cache hit
ratio?
0. Explain the difference between a hot backup and a cold
backup and the benefits associated with each


1. You have just had to restore from backup and do not have
any control files. How would you go about bringing up this
database?


2. How do you switch from an init.ora file to a spfile?


3. Explain the difference between a data block, an extent
and a segment.


4. Give two examples of how you might determine the
structure of the table DEPT.


5. Where would you look for errors from the database engine?


6. Compare and contrast TRUNCATE and DELETE for a table.


7. Give the reasoning behind using an index.


8. Give the two types of tables involved in producing a star
schema and the type of data they hold.


9. What type of index should you use on a fact table?


10. Give two examples of referential integrity constraints.


11. 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?


12. Explain the difference between ARCHIVELOG mode and
NOARCHIVELOG mode and the benefits and disadvantages to
each.


13. What command would you use to create a backup control
file?


14. Give the stages of instance startup to a usable state
where normal users may access it.


15. What column differentiates the V$ views to the GV$ views
and how?


16. How would you go about generating an EXPLAIN plan?

Answer Posted / umesh h

1.If Buffer cache hit ratio is less then 85%.
2.Hot backup is online backup(means we can take backup when
database is up and running.ie Alter database begin backup
mode;
Cold backup is offline backup(means taking backup when
database is shutdown gracefully.ie at O/S level using copy
command.)
3.Create controlfile dynamicaly.
4.create spfile from pfile;
startup force;
5.oracle stores data interms of datablocks
group of datablocks is known as extent.
group of extents make a segment.
6.Truncate=delete+commit(as it is a DDL command)
Delete= as it is a DML command we can rollback the
transaction.
7.reason behind using index is to increase query
performance.(most suitable for DWH).
Cont.... in next answer

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