This means that the number can have approximately 11 digits of precision, or significant places. Contrast this with single-precision floating point, where only five digits can be stored accurately. Variable and Fixed Length strings Variable and fixed length strings are both types of field whose value is a simple string of characters. Fixed-length strings will always have the same number of characters in them. Logical Logical fields represent simple truth values - Yes or No, True or False.
Logical fields can only ever take one of two values.
If values other than 0 and 1 are used in the field, the attributes column describes the values used to represent true and false for the field. If a field is known to be a fixed number of characters or bytes, the 'length' describes the number of characters or bytes used to store the field.