Entry

What is the relationship between items, SKUs, attributes and variations?

Aug 10th, 2000 10:37
C Walker,

An item is the lowest level.  It has the basic information such as a 
Name and Description and Pictures, and it is categorized into one or 
more departments.
An item must have one or more SKUs.  A SKU contains the Price and 
Shipping information.  For example, if you are selling books, each 
Title (not physical book) would become an item, and you could have 2 
SKUs for a particular item: one for Hardcover and one for Softcover.  
Hardcover books vs. Softcover books differ in their pricing and 
availability, but also share some common information like Title and 
Author.
SKUs can have 0 or more attributes.  An attribute is a property of a 
SKU that does not affect price or availability.  For example, if you 
are selling T-Shirts, you might want to have a color attribute.
Attributes can have 1 or more variations.  An attribute with 1 
variation is a special case - and example that is included with 
Freetrade is the gift wrap.  For attributes with more than 1 variation, 
a drop-down list (by default) is display on the item screen.  The 
values of the drop-down list are the variations.  So, keeping with the 
T-Shirts example, if you have a color attribute associated with the 
SKU, you might have several colors (Yellow, Red, Green, Blue) 
associated with the color atribute.  Those colors would be in the drop-
down list of the item.
SKUs can have more than one attribute, each attribute will be a 
seperate drop-down list.  If you are selling T-shirts and you have the 
same number of T-Shirts in each size and each color, and they all cost 
the same, you might just set up one SKU with two attributes, one for 
size (ie S, M, L) and one for color (ie Yellow, Red, Green, Blue) and 
the customer can choose any combination (ie Mary wants a M Green, John 
wants a L Yellow)
Also note that attributes can be used for more than one item.  Say you 
have one item that is a T-Shirt, and one item that is a Sweatshirt.  
(or you could even have one item, with 2 SKUs, one for Tshirt and one 
for Sweatshirt, if you really wanted)  The SKUs can use the same color 
attribute.  But you can pick and choose which specific colors each one 
is available in, without having to make multiple attributes.  So, T-
Shirts might come in Yellow, Red, Green, and Blue, but sweatshirts only 
come in Red and Blue.