The hanging fixture over the table should be at least 12 inches smaller than the width of your table. It is always better to go larger than smaller to avoid a fixture that is out of proportion to the room size. If your table measures 44 inches wide, your chandelier should be 32 inches wide.
Make sure the fixture is not hung higher than 36 inches above the table. Fixtures that are too high will create a glare and not produce enough light for the table. They also will create unattractive shadowing in your space.
Another option for lighting is to use two fixtures instead of one. Two fixtures create more size in length, making a smaller fixture look larger. However, the same rules apply for the hanging height.
When choosing a chandelier, consider light output. Most chandeliers use candelabra bulbs, which are typically lower in wattage. A larger chandelier will have six or more bulbs, and a tiered chandelier will have as many as 12. Have your electrician install a dimmer switch and you'll be able to control the lighting easily and never be in the dark.
Lighting and do-it-yourself stores have lighting specialists on staff to help you select your fixture. Many have charts and recommendations that can help you choose the best fixture for your lighting and decorating needs.