Re: Normalization

In article <20000801205747.25110.00000257_at_ng-cr1.aol.com>,   gryspr_at_aol.com (GrySpr) wrote:
> I have tried to pick up on the idea of normalization, but still do not
> understand. Can anyone give me some imput that would make
>understanding it

Normalizing is a process of reducing data until every record in every table is unique.

In other words, instead of storing SupplierName, SupplierAddress, SupplierFavoriteColor with every item in an inventory list, you'd store all of the supplier information in a supplier table, and use a key (could be the supplier number, or some other unique value) and use it as a field in the inventory table. i.e.: [Suppliers table]
[Supplier Number][SupplierName][SupplierFavoriteColor]

 0001             BOGUS INC     RED
 0002             BOGUS2 INC    BLUE

[Inventory table]
[SupplierNumber][ItemNumber][Itemqty]

 0001            SAP1000     20
 0001            SAP1001     200
 0002            SAP1231     10

Notice that *NONE* of the supplier info, except the key value of course, needs to be repeated. We can still tell that item SAP1000 is supplied by someone who likes RED, but it is only recorded once.

In a fully normalized database, this kind of reduction can be carried on for many levels, and sometimes even requires adding tables simply to preserve the normalization. Note that normalization essentially is a process of forcing data into one-to-many relationships, and one-to-one relationships are also easily formed in a normalized database, but many- -many relationships remain a problem.

Sent via Deja.com http://www.deja.com/
Before you buy. Received on Thu Aug 03 2000 - 00:00:00 CEST