Reference: Numeric Types

Numerics are numbers that are typically used to represent counters or identifiers. They are useful when exact precision is needed and rounding errors need to be exact, e.g., when storing monetary amounts. Numeric types offer a fixed amount of decimal precision, and a fixed scale of fractional digits.
CedarDB supports two different storage widths, an eight-byte numeric, and a sixteen-byte bignumeric. Type specifications can use both names, as well as decimal(precision, scale), interchangeably. CedarDB will choose the underlying representation automatically based on the specified precision.

Usage Example

create table example (
    price numeric(38, 3),
    tax_rate numeric(5, 2)
insert into example values
    (123.45, 0.19),
    (1000, 0);
select * from example;
  price   | tax_rate 
  123.450 |     0.19
 1000.000 |     0.00
(2 rows)

Value Range

Type (precision, scale)MinMaxUnderlying
numeric(18, 0)-922337203685477580892233720368547758078 Byte
numeric(18, 3)-9223372036854775.8089223372036854775.8078 Byte
numeric(38, 0)-17014118346046923173168730371588410572817014118346046923173168730371588410572716 Byte
numeric(38, 6)-170141183460469231731687303715884.105728170141183460469231731687303715884.10572716 Byte
Operations on 16 Byte types are expensive to compute. We recommend using a precision of 18 or less when possible for your application.

Storing values outside of the supported ranges will result in an overflow exception. Operations on numerics are range checked, so that e.g., numeric overflows will never cause wrong results.

Handling Overflows


create table numerics(i) as 
values (power(2, 126)::numeric(38,0));

The following will produce an overflow, since $2^{126} + 2^{126} > 2^{127}-1$.

select i + i from integers;
ERROR:  numeric overflow

Wrapping the operation in a try() produces a null value for overflows:

select try(i + i) from numerics;
           <---- null
(1 row)