A Study of LY2599506 (Oral Agent Medication: Glucokinase Activator 1) in Type 2 Diabetes Mellitus

The purpose of this study is to help answer the following research question(s): * To test if taking LY2599506 for 12 weeks controls blood sugar better than taking glyburide for 12 weeks. * To evaluate the safety of LY2599506 in participants with diabetes. * To determine if LY2599506 has the ability to control blood sugar in participants with diabetes. * To determine how much LY2599506 should be given to participants. * To determine if LY2599506 has an effect on a participant\'s weight. The study design consists of 4 study periods: a screening period, a 4-week dose adjustment period, an 8-week treatment period, and a 4-week follow up period.