view and materialized view

[#1]

Hi Experts,

1.Difference between Table and View.

2.Difference between View and materialized view.

3.Is it possible to update the data using view.

Could you please any one help me..

Thanks&Regards

Ramesh

[Former Member]

Hai Ramesh,

Materialised View:Materialized views are schema objects that can be used to summarize, precompute, replicate, and distribute data.It provides indirect access to table data by storing the results of a query in a separate schema object. Unlike an ordinary view, which does not take up any storage space or contain any data.

Senario:While creating a dataware house we need to go for staging part at that time this is useful.

VIEWS:

We have 2 types

1)Read only

2)Updatable

An updatable view lets you insert, update, and delete rows in the view and propagate the changes to the target master table.

In order to be updatable, a view cannot contain any of the following constructs:

SET or DISTINCT operators, an aggregate or analytic function, a GROUP BY, ORDER BY, CONNECT BY, or START WITH clause, a subquery (or collection expression) in a SELECT list

or finally (with some exceptions) a JOIN

Views that are not updatable can be modified using an INSTEAD OF trigger.

Hope this helps you,

Thanks & Regards

Pujitha