What is Massively Parallel Processing (MPP)

With the advent of Big Data sets mainstream technologies like Massively Parallel Processing (MPP) systems is experiencing vital growth. Let’s discuss about what is MPP or Massively Parallel Processing (MPP)

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

http://dwhlaureate.blogspot.in/2012/08/sub-queries-in-oracle.html

Now will see how to use correlated update and delete statements