Literals are used to represent data in a direct format. Examples of standard types of literals are:

          integer - 0, -34, 45, 0X080000000;
          real - 0.0, -3.14, 3.23e-23;
          string - 'text', 'don''t!';
          date - DATE '10.01.2014';
          time - TIME '15:12:56';
          timestamp - TIMESTAMP '10.01.2014 13:32:02';
          null state - null
     

Details about handling the literals for each data type are discussed in the next chapter, Data Types and Subtypes.