The REAL data type provides 4 bytes of storage for numbers using IEEE floating-point notation.
REAL value ranges:
These limits are different from the java.lang.Float Java type limits.
An exception is thrown when any double value is calculated or entered that is outside of these value ranges. Arithmetic operations do not round their resulting values to zero. If the values are too small, you will receive an exception. The arithmetic operations take place with double arithmetic in order to detect under flows.
-- this example will fail because the constant is too long: values 01234567890123456789012345678901e0;
When mixed with other data types in expressions, the resulting data type follows the rules shown in Numeric type promotion in expressions.
Constants always map to DOUBLE PRECISION; use a CAST to convert a constant to a REAL.