How do tablets control diabetes?

Multiple ways. Some of the tablets increase the amount of Insulin the pancreas makes. Others make the tissues more sensitive to insulin, others keep the liver from producing glucose.
Insulin Regulation. They control diabetes by either increasing your body's production of Insulin or by decreasing resistance to the Insulin that your body naturally creates, or both.
Many different ways. There are 8 classes "tablets" to control diabetes with a 9th class to be available soon. They decrease glucoses in many different ways including: blocking the absorption of carbohydrates from the gut or increasing: 1) Insulin production 2) Insulin sensitization of the liver, fat tissues, & muscle 3) glp-1 levels or 4) Dopamine levels in the brain the new medication class works in the kidney.
By affecting insulin. There are several different pills to treat diabetes. The most commonly used is an old drug called metformin. This medication makes the Insulin your body makes work better so you need less of it to reduce blood sugar. Other meds, such as Glipizide work by squeezing more Insulin out of our pancreas. Almost all meds work on one of these two loose principles.
Different modes. Different pills treat diabetes differently. There are biguanides, sulfonylureas, tzd's, dpp-4 inhibitors, and meglitinides. You'll need to discuss these different options with your physician. Each one has different mechanisms of action too complex to discuss here.
Irrelevant. Question. Tablet could mean any tablet, therefore it has no chem, it can not control diabetes.
They can. Most diabetes is acquired in adulthood and is initially well treated with pills. Some of the pills are metformin, glyburide, januvia, (sitagliptin) and other related medicines. As time goes by, however, some diabetics need to add Insulin to their treatment plans.
Help process sugar. Most diabetic pills/tablets help your body metabolize sugar (glucose) better. Some pills also reduce the absorption of food to lower sugar levels.
Many ways. Metformin stop the liver from releasing excess sugar. Actos overcomes Insulin resistance in the muscles. When food is in the intestines, onglyza, januvia, or tradjenta (linagliptin) 1) stimulate release of sugar from the pancreas, 2) stop sugar release from the liver, 3) slow stomach emptying making you feel full, and 4) give your brain the "full" signal so you stop eating. These can be taken in combination.
2 major ways. The major players work by 1. Increasing the Insulin sensitivity (metformin). 2. Increasing the amount of Insulin released at the time the pill is taken (glipizide, glyburide). There are additional medications that work on other subtle factors in glucose utilization (januvia) but these are often sought after the other methods have failed.
Various ways. Different medications by mouth control blood sugar in different ways. Some help your pancreas release more Insulin to bring sugar down. Some help keep your liver from releasing blood sugar into the bloodstream when it is not necessary. Some help your body utilize its own Insulin more efficiently. Some replace hormones that are deficient diabetes to increase Insulin and decrease sugar.
See below. (1) people in families with type 2 diabetics have a 90% chance of getting diabetes. (2) obese people are more likely to have diabetes due to increase fat tissue causing resistance to insulin.