Difference Between Clustered Index and non Clustered Index

hi all, can u tell me what is basic difference beween
clusterd index and non clusterd index?
Thanks in advance
hrishikeshHello Hrishikesh !
Quioted from DBA-Forum:
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Assuming SQL 7 or 2K:
A clustered index orders the table and is loaded into memory. SQL Svr
accesses data in the table by directly accessing the Index.
A non clustered index does NOT order the data. It establishes a list of the
locations of the data pages containing the column(s) of the index.
So a clustered index organizes the data for maximum efficient access and a
non clustered index does not.
If you create an index on a field that is NOT in the WHERE clause of a
query, you gain absolutely nothing. Actually, you take a hit because you are
wasting drive space, query time and memory space on a useless index.
If you create an index (Clustered or non clustered) that IS in the WHERE
clause, you will gain a benefit because the index points to the data.
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HTH, Jens Süßmeyer.|||BOL says:
A clustered index determines the physical order of data in a table. A
clustered index is analogous to a telephone directory, which arranges data
by last name. Because the clustered index dictates the physical storage
order of the data in the table, a table can contain only one clustered
index. However, the index can comprise multiple columns (a composite index),
like the way a telephone directory is organized by last name and first name.
Nonclustered indexes have the same B-tree structure as clustered indexes,
with two significant differences:
a.. The data rows are not sorted and stored in order based on their
nonclustered keys.
b.. The leaf layer of a nonclustered index does not consist of the data
pages.
"Hrishikesh Musale" <musaleh@.mahindrabt.com> wrote in message
news:0da301c36d4f$2ca746f0$a101280a@.phx.gbl...
> hi all, can u tell me what is basic difference beween
> clusterd index and non clusterd index?
> Thanks in advance
> hrishikeshsql