Introduction To NewSQL

NewSQL is a new class of Databases products that offers high performance and scalability like NoSQL for online transaction processing and also incorporates the relational database properties like SQL and ACID (atomicity, consistency, isolation and durability) transactions.

The NewSQL architecture (distributed systems architecture) significantly reduces overhead and is proficient of running on a large number of nodes without suffering bottlenecks. Also they conserve the high-level language query potential of SQL. NewSQL is now considered as an alternative to NoSQL. 

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.

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.

Syntax:

create [or replace] [force|noforce] view

<view_name> [column_alias_names_separated_commas]

as <subquery>[with [check option] [constraint constraint_name] [with read only]];

VIRTUAL COLUMN IN ORACLE 11G

Virtual Column is one of the new features introduced in Oracle 11g.The syntax for defining a virtual column is:

Column_Name [Datatype] [GENERATED ALWAYS] AS [Expression] [VIRTUAL]

Here, Data type: Column’s Data Type and Expression: SQL Expression

Though Virtual Columns appear to be like normal table columns they are defined by an expression and they derive their value from the result of the expression. The values of these virtual columns are not stored in database; instead they are calculated at run time dynamically.