what are indexes..how many types of index's are there and
what are they?
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Answer / rudrab123
An index is a listing of keywords accompanied by the
information of location of the subject.
in a SQL statement, if there is no Where clause then there
is no index.
In Oracle 8i,
there are 4 types of indexes .They are:-
1.B-Tree Index
2.Bitmap Index
3.Unique index
4.Function based index.
| Is This Answer Correct ? | 9 Yes | 1 No |
Answer / rudrab123
Answer 1 is not he basic function of Index in Oracle or any
databse.
Generally speaking,attaching index to a column in a table,
information of the location of the different values in the
indexed column is also provided.This address is like the
pointer varible in C,and in SQL it is called ROWID(a
pseudocolumn).Let us see he example ....
SQL>select * from students
where id=123;
Students is a databse table and ID is the column in the
table on which we create the index.
On execution of the above query, at first, the ROWID
corresponding to id=123 in students table is found.From
this rowid, the index value for the row of data which is
pointed to by ROWID is found(in very less time).And so the
row is idenified and the entire row data is displayed.
The above serach process is specifically called "TABLE
ACCESS FULL(USING ROWID)).
| Is This Answer Correct ? | 3 Yes | 2 No |
Answer / guest
when queries are run against a DB,an index on that DB
basically helps in the way the data is sorted to process
the query for faster data retievals.
There are basically two types of indexes that we use in SQL
Server. Clustered and the Non-Clustered.
| Is This Answer Correct ? | 6 Yes | 6 No |
Answer / bhargav kesavan
Indexes are used to do a faster search. i.e; easy way to
retrive data.
There are two types are indexes:
1> B-Tree Indexes.
2> Bitmap indexes.
| Is This Answer Correct ? | 1 Yes | 1 No |
Answer / ted
There are four types index:
1)Bitmap index
2)Dense index
3)Sparse index
4)Reverse index
| Is This Answer Correct ? | 2 Yes | 2 No |
Answer / a.brahmam
indexes 5 tyeps
1.B-Tree index:-->in oracle by default index is called B tree index.
2.Bit map index:--->in oracle Bit map index is used to data warehouse applications generally Bit map index created low cardinality columns.
3.function based index:--->B tree index extension of the function based index.
in B tree indexes two type this are
4.Unique B tree index in oracle by default automatically created.
5.Non-Unique B tree index in oracle by default manually created.
| Is This Answer Correct ? | 0 Yes | 0 No |
Answer / 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
| Is This Answer Correct ? | 0 Yes | 1 No |
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