This extension provides a product matrix for Simple Invoices. This means that in invoice creation you can select a product and then a list of attributes and values will be display that are relevant to that product for you to choose from.
ie. - Product = T-Shirt - Product Attributes = Size, Colour - Product Values = Size (Small, Medium, Large), Colour (Red, White, Blue)
In the Manage Product Values screen you can add new values and assign them to certain attributes, and in edit/add products you can assign attributes to a certain product.
This extension is currently work in progress
There are modifications required to the Simple Invoices database for this extension to work
They are detailed in ./extensions/product_matrix/install/matrix.sql
You can just import this .sql file into phpMyAdmin for the db changes to be applied
You need to edit ./config/config.php and enable the product matrix extension, refer how_to_enable_an_extension for how to do this
Product attributes are the group of values that a product can have ie for the product 'T-shirt' it may have product attributes of size and colour
Product values is the assigning of multiple values to a product attribute ie for the product 'T-shirt' with product attributes of size it may have product values of Small, Medium, and Large
This extension was developed by Justin Kelly of SixHQ
This extension is released under the GNU GPL v3