Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 8: Being Normal: Normalization and Other Basic Design Issues
Sometimes what is, in practice, one entity still needs to be broken out into two tables and, thus, two entities.
The header is something of the parent table of the two tables in the relationship. It contains information
that needs to be stored only once while the detail table stores the information that may exist in
multiple instances. The header usually keeps the name of the original table, and the detail table usually
has a name that starts with the header table name and adds on something to indicate that it is a detail
table (for example, OrderDetails). For every one header record, you usually have at least one detail
record and may have many, many more. This is one example of a kind of relationship (a one-to-many
relationship) that you look at in the next major section.
So let’s take care of this by splitting our table again. We’ll actually start with the detail table since it’s
keeping the bulk of the columns. From this point forward, we’ll call this table OrderDetails:
OrderNo
(PK)
LineItem
(PK)
PartNo Description Qty Unit
Price
Then we move on to what, although you could consider it to be the new table of the two, will serve as
the header table and thus keep the Orders name:
OrderNo (PK) OrderDate CustomerNo
100 1/1/1999 54545
101 1/1/1999 12000
102 1/1/1999 66651
103 1/2/1999 54545
Total
Price
100 1 1A4536 Flange 5 15 75 6
100 2 OR2400 Injector 4 27 108 .5
100 3 OR2403 Injector 4 29 116 .5
100 4 4I5436 Head 1 750 750 3
101 1 3X9567 Pump 1 62.50 62.50 5
102 1 8G9200 Fan 7 12 84 3
102 2 8G5437 Fan 1 15 15 3
102 3 3H6250 Control 1 32 32 5
103 1 8G9200 Fan 40 12 480 3
103 2 2P5523 Housing 1 165 165 1
103 3 3X9567 Pump 1 42 42 5
Wt
223