Designing an 'Order' schema in which there are disparate product definition tables

Table Product ( id PK, name, price, units_per_package)
Table Product_Attribs (id FK ref Product, AttribName, AttribValue)

Table Product (id PK, name, price, units_per_package, attrName_1, attrValue_1 ...)

Attribute(attribute_id, description, is_listed)
-- contains values like "colour", "width", "power source", etc.
-- "is_listed" tells us if we can get a list of valid values:

AttributeValue(attribute_id, value)
-- lists of valid values for different attributes.

Product (product_id, description)

ProductAttribute (product_id, attribute_id)
-- tells us which attributes apply to which products

Order (order_id, etc)

OrderLine (order_id, order_line_id, product_id)

OrderLineProductAttributeValue (order_line_id, attribute_id, value)
-- tells us things like: order line 999 has "colour" of "blue"