what are indexes..how many types of index's are there and
what are they?

Answer Posted / test

Index simply means sorting of data. Let u stake an example :

EmpID Name
1 A
6 B
5 C
9 D
...
...
2 ZZ

Now if we create index (Talking about btree index) on EmpId
it means creating a segment with the following in sorted
order
EmpId Rowid
1 <some value>
2 ....
5 ...
6 ...
...

Now if we want to search with EmpId, it will do a binary
search and get the rowid in few searches

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