Tuesday, 15 April 2014

Update and Delete in Correlated Sub query

Correlated sub queries as you all know are used for row-by-row processing. Here each sub query is executed once for every row of the outer query. The oracle server performs a correlated subquery when the subquery references a column from a table referred to in the parent statement. 

The general for of a correlated subquery is:
select column1, column2, . . . . . . .
from table1 outer
where [column1] operator (select column1, column2,
from table2 where expr1= outer.expr2);

To read more about Sub queries please refer our previous post

Now will see how to use correlated update and delete statements 

Friday, 21 March 2014

“ VoltDB ” - NewSQL DBMS For High Velocity Applications

VoltDB is a high performance scalable RDBMS and NewSQL Database primarily for Big Data, high velocity OLTP and Real-time analytics designed by Michael Stonebraker, Sam Madden, and Daniel Abadi.

It was one of the NewSQL databases first introduced as open source product in 2010.Demand for high scale and in memory databases(which means it depends mainly on main memory for storage) in the market has shaped great aperture for VoltDB.

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