Data Type

1. A data type is a set of values that can be represented.

2. A value is either a NULL value (undefined value), or a non-NULL value.

3. The NULL value is a special value. The comparison of the NULL value with all values is undefined.

4. A non-NULL value is a character string, a number, a date value, or a value of a LONG column.

See also:

Character String

LONG Column

Number

Date Value