Type 2 diabetes
Type 2 diabetes has traditionally been known as late-onset diabetes, and it is the great scourge of the Western or supposedly developed world. The main difference between Type 1 diabetes and Type 2 diabetes is that Type 2 patients - at least initially - have "normal" insulin in their blood streams, though their body doesn't know how to use it (they are said to be insulin resistant). Another important difference is that Type 2 diabetic patients are much less prone to ketoacidosis, though they are not totally exempt from it.
Because Type 2 diabetics are initially different from Type 1 diabetics (i.e., they have insulin initially), they are treated differently. Since their cells are insulin resistant, one way of treating it is by inducing increased insulin production. As the days turn into months, and the months into years, the β-cells of the pancreas stop producing insulin, though the reason for this is not clear. Once the &beta-cells have stopped producing insulin, they might as well be Type 1 diabetics.
Being overweight is one of the key risk factors for Type 2 diabetes, since it increases insulin resistance. Therefore, at least initially, Type 2 diabetes can be easily treated with exercise and weight loss. Sadly, this is the one treatment patients do not want, instead preferring a magic pill or silver bullet. So, physicians do what they gotta do, but should always understand that exercise and weight loss are the best treatment of Type 2 diabetes before the patient becomes insulin-dependent (i.e., Type 1 diabetes).
Since Type 2 diabetics are frequently not completely insulin resistant, increasing insulin production (i.e., inducing hyperinsulinemia) may suffice. One of the drugs involved in this is sulfonylurea, which stimulates the pancreas to produce more insulin. This is univerally considered a bad idea, but is still widely used. Another drug used for Type 2 diabetics is metformin (generic name), which improves the use of glucose.