One school of thought that developers have about primary keys is to add an additional column to uniquely identify each record. Which is another school of thought? Primary keys should not be used at all.
A primary composite key should be used.
Find unique values already in the data.
A default identifier should be created.

Which of the following statements regarding the southern economy at the end of the nineteenth century is accurate? the south was producing as much cotton as it had before the civil war.

The quinoa seed is in high demand in wealthier countries such as the u.s. and japan. approximately 97% of all quinoa production comes from small farmers in bolivia and peru who farm at high elevations—8,000 feet or higher. the seed is considered highly nutritious. mostly grown and harvested in bolivia and peru, and sold to markets in other countries, the seed is now considered an important for these nations. the governments of bolivia and peru are hopeful that this product will increase the quality of life of their farmers.

Four key marketing decision variables are price (p), advertising (a), transportation (t), and product quality (q). consumer demand (d) is influenced by these variables. the simplest model for describing demand in terms of these variables is: d = k – pp + aa + tt + qq where k, p, a, t, and q are constants. discuss the assumptions of this model. specifically, how does each variable affect demand? how do the variables influence each other? what limitations might this model have? how can it be improved?