Tuesday, 18 February 2014

Invisible Indexes - Oracle 11g New Feature

Before 11g, Oracle didn’t have the facility to make an Index Invisible or visible……

Invisible Indexes, as the name imply is invisible to the optimizer except when we explicitly make it visible. When an index is made invisible it remains unavailable for the optimizer while running execution plans for queries. While running execution plans the optimizer decides which indexes to be used for faster execution.

Wednesday, 5 February 2014

View and Base Tables (Dropping of View)

What is a View?
A view is a logical table based on one or more tables or another view.View can be thought as a virtual table which takes the output of a query and stores it.

create [or replace] [force|noforce] view
<view_name> [column_alias_names_separated_commas]
as <subquery>[with [check option] [constraint constraint_name] [with read only]];

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