Range, precision, and storage size

The real and double precision types are built on types supplied by the operating system. The float type accepts an optional binary precision in parentheses. float columns with a precision of 1–15 are stored as real; those with higher precision are stored as double precision.

The range and storage precision for all three types is machine dependent.

Table 1-10 shows the range and storage size for each approximate numeric type. Note that isql displays only 6 significant digits after the decimal point and rounds the remainder:

Table 1-10: Approximate numeric datatypes


Bytes of storage

float[(default precision)]

4 for default precision < 16

8 for default precision >= 16

double precision