Answer / sa123

For good performance Index is required.
Consider the case of a very large table (20,000,000 rows)
to which new records are added daily (usually about 1,000
of them). Every night, you need to report these additions
on an audit trail. Rather than scan the whole table looking
for changes, you will want to use an index over the
TRANSACTION_DATE column. But the index would need to be
huge. This is a case in which your index is over the entire
table, although you are actually interested only in the
1,000 or so records that were added today. The actual index
is physically many times larger than it needs to be, and it
uses many more disk I/Os to traverse the binary tree to the
leaf data.

Answer / samar singh

Index by tables are composed of two components
1)primary key of binary_interger
2)column of scalar or record type

and used for increasing the size dynamically.

Answer / opulentus

opulentus

Give the order of sql select?

0 Answers  

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i have a table t1 a math 20 b phy 30 cchemisty 10 a math 40 b phy 23 c che 21 a math15 bphy 33 c che 56 write a quire to find out the max markr of each subject

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If the base table structure is changed what will happen to join index????

2 Answers  

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1. what is the exact use of hint in sql. 2. How we can avoid index scan in sql even though index is there in the table.

1 Answers   Polaris,

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What is case function?

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What is the purpose of using pl/sql?

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Explain table and field in sql?

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What is trigger in pl sql with examples?

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How do you get all records from 2 tables. Which join do you use?

8 Answers   Microsoft,

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What is the difference between python and sql?

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What is meant by cursor in sql?

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