Answer Posted / andrew g avelin

difference between Cluster index and non cluster indexing?

A clustered index is a special type of index that reorders
the way records in the table are physically stored.
Therefore table can have only one clustered index. The leaf
nodes of a clustered index contain the data pages.

A nonclustered index is a special type of index in which
the logical order of the index does not match the physical
stored order of the rows on disk. The leaf node of a
nonclustered index does not consist of the data pages.
Instead, the leaf nodes contain index rows.
------------------------

The difference between them lies in what the leaf-level
nodes -- the lowest level of the tree -- contains. In a
clustered index the leaf-level is the data, while the
leaves of a non-clustered index contains bookmarks to the
actual data. This mean that for a table that has a
clustered index, the data is actually stored in the order
of the index. What the bookmarks of the non-clustered index
point to depends on if the table also has a clustered index
or not. If it does have a clustered index then the leaves
of non-clustered indexes will contain the clustering key --
the specific value(s) of the column(s) that make up the
clustered index -- for each row. If the table does not have
a clustered index it is known as a heap table and the
bookmarks in non-clustered indexes are in RID format
(File#:Page#:Slot#), i.e. direct pointers to the physical
location the row is stored in

------------------------

(1)CLUSTERED INDEX
(2)NON-CLUSTERED INDEX

CLUSTERED INDEX :

(A) Data is restored in case of this index.CLUSTERED INDEX
is unique of nay given table and we can have only one
CLUSTERED INDEX on a table

(B) Leaf Level of CLUSTERED INDEX is Actual Data.

Non-CLUSTERED INDEX :

(A) We can have as many Non-CLUSTERED INDICES on the
Database.

(B) Leaf Level on NON_CLUSTERED INDEX is pointer to the
data in rows .

I hope u've got the differences b/W them.
------------------------

CLUSTERED INDEX:
Clustered index will be created by default when u
create primary key on a column. So we can create one
clustered index per table. clustered index is stored in
serial passion.

NON CLUSTERED INDEX:
Non clustered index will be created automatically when u
create unique key on a column. A table can have no.of
unique keys, so we can create no.of non clustered indexes
per table.

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Hi how to import oracle sequence in Informatica? Please write stored procedure code that will import oracle sequence in Informatica SP transformation as per below scenario Oracle table product list Pro_id, pro_name 101, LED Lights. 102, 20watt CFL Lights. 103, 30 watt CFL lights Now a new flat file with new product list needs to be added to oracle table product list with oracle sequence. flat file product Prono,pro_name, 1, 20 watt tube light 2, 30 watt tube light & target should be like 101, LED Lights. 102, 20watt CFL Lights. 103, 30 watt CFL lights. 104, 20 watt tube light 105, 30 watt tube light thks reg suvarna joshi suvarnaatsuvarna@rediffmail.com

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