For last few days I was busy packing my things plus doing some important task related to my Australia trip but at last got time to write about something new in Oracle 11g called Virtual Columns.
First lets go through one situation, we have a sales table with Gross_Amount and Discount_Amount.
Now
Net_Amount := Gross_Amount - Discount Amount;
We can tell our guys to use this formula everywhere. Now if formula changes due to some reason, then we will need to change the formula everywhere.
Other way to tackle such situation is to create the separate view (formula embedded in it) and everybody use that […]

[Read more →]

Recently I came across term called Virtual Index or some call it fake indexes. I will use term Virtual Index to refer these indexes.
This type of indexes has been extensively used by most Oracle Tuning Tools in the market. You can say almost all the tools which promise to give “if then analyzes” on execution plan, must be using this capability.
In simple words it allow us to simulate the existence of an index and test its impact without actually building a actual index. This saves lot of time and most important I/O from and to Oracle resources (Disk, CPU, etc).
Once […]

[Read more →]