Floating point number A floating-point number represents a limited-precision rational number that may have a fractional part. Integer An integer data type can hold a whole number, but no fraction. Integers may be either signed (allowing negative values) or unsigned (nonnegative values only). Controlled list A predefined list of strings that a user can select from. ODM2 Property Data Type Controlled Vocabulary ODM2 Working Group A vocabulary for describing the data type for an extension property in ODM2. Extension properties can be added to many of the entities in ODM2 (e.g., Sites, Variables, etc.). The values of these extension properties must be of one of the listed primitive data types. Boolean A boolean type is typically a logical type that can be either "true" or "false". String An array of characters including letters, digits, punctuation marks, symbols, etc.