field: Fields describe a single aspect of each member of a table. A student record, for instance, might contain a last name field, a first name field, a date of birth field and so on. All records have exactly the same structure, so they contain the same fields.
Many jurisdictions require one or more bicycle lights to be fitted to bicycles ridden at night â generally a white light in the front and a red light at the back.
To produce light when the bike is stationary, some dynamo lights have a stand light facility, usually a single blue-white (front light) or red (rear light) LED powered by a capacitor, which runs for around five minutes.n Germany, it was illegal to use bicycles without a dynamo-based lighting system except on racing bicycles below 11 kg. This stimulated the market in Germany for high quality dynamos. Since 5 July 2013, a change in the law allows use of battery-powered lights.