Database normalization-Does having a 'total' field in a header table violate any rule of normalization

Question

Datebase Normalization attempts to, among other things, eliminate redundant data. Lets say I have 2 tables, an Invoice Header Table and an Invoice Line Item Table. For every invoice, there will be 1 header record and a line item record for each line item of course. The header record contains a field that is the sum of the 'price' field in each line item record. This is redundant since you could simply sum the 'price' fields in each line item record but having it already summed speeds processing. Does this redundancy violate any rules of normalization?

Answer 1

It's not technically a redundant field, like having two tables with a list of the same 10 countries.

The only caution is to be certain the total is updated any time one of the prices are. Otherwise you could have an incorrect total drawn from the data.

From a normalization standpoint, you're not in violation of any level of normal form. A normalization 'purist' might object on some principal, but like all things, there is a theoretical view and a practical view.

In practice, you've found that having the total speeds up your processing, and in the real world, time is money. So faster processing outweighs any purist thought of perfect normalization.

Answer 2

normalisation potential changing a foul layout of database right into a solid layout. an unnormalised DB is before everything converted to 1st widely used type in basic terms then it extremely is extra converted to 2d NF then to third nd so on... think we've a DB table(unnormalised potential it incorporate redundant records) then we create a seperate table for that records it extremely is redundant.