Sql server® 2012 t-sql fundamentals

orderid

productid

PK

PK

orderdate

qty

customerid

companyname

FIGuRE 1-1

  Data model before applying 2NF. 

The second normal form is violated in Figure 1-1 because there are non-key attributes that de-

pend on only part of a candidate key (the primary key, in this example). For example, you can find 

the order date of an order, as well as customerid and companyname, based on the orderid alone. To 

conform to the second normal form, you would need to split your original relation into two relations: 

Orders and OrderDetails (as shown in Figure 1-2). The Orders relation would include the attributes 

orderid, orderdate, customerid, and companyname, with the primary key defined on orderid. The 

OrderDetails relation would include the attributes orderid, productid, and qty, with the primary key 

defined on orderid and productid.

Orders