postgres_datatype1.htm
Work In Progress:

Reference : http://www.postgresql.org/docs/9.2/static/datatype-numeric.html#DATATYPE-NUMERIC-TABLE

Data Types

Name Aliases Description
bigint int8 signed*1 eight-byte integer
bigserial serial8 autoincrementing eight-byte integer
bit [ (n) ]   fixed-length bit string
bit varying [ (n) ] varbit variable-length bit string
boolean bool logical Boolean (true/false)
box   rectangular box on a plane
bytea   binary data ("byte array")
character [ (n) ] char [ (n) ] fixed-length character string
character varying [ (n) ] varchar [ (n) ] variable-length character string
cidr   IPv4 or IPv6 network address
circle   circle on a plane
date   calendar date (year, month, day)
double precision float8 double precision floating-point number (8 bytes)
inet   IPv4 or IPv6 host address
integer int, int4 signed four-byte integer
interval [ fields ] [ (p) ]   time span
json   JSON data
line   infinite line on a plane
lseg   line segment on a plane
macaddr   MAC (Media Access Control) address
money   currency amount
numeric [ (p, s) ] decimal [ (p, s) ] exact numeric of selectable precision
path   geometric path on a plane
point   geometric point on a plane
polygon   closed geometric path on a plane
real float4 single precision floating-point number (4 bytes)
smallint int2 signed two-byte integer
smallserial serial2 autoincrementing two-byte integer
serial serial4 autoincrementing four-byte integer
text   variable-length character string
time [ (p) ] [ without time zone ]   time of day (no time zone)
time [ (p) ] with time zone timetz time of day, including time zone
timestamp [ (p) ] [ without time zone ]   date and time (no time zone)
timestamp [ (p) ] with time zone timestamptz date and time, including time zone
tsquery   text search query
tsvector   text search document
txid_snapshot   user-level transaction ID snapshot
uuid   universally unique identifier
xml   XML data
 
Numeric

Numeric Types

Numeric types consist of two-, four-, and eight-byte integers, four- and eight-byte floating-point numbers, and selectable-precision decimals.

Numeric Types

Name Storage Size Description Range
smallint 2 bytes small-range integer -32768 to +32767
integer 4 bytes typical choice for integer -2147483648 to +2147483647
bigint 8 bytes large-range integer -9223372036854775808 to 9223372036854775807
decimal variable user-specified precision, exact up to 131072 digits before the decimal point; up to 16383 digits after the decimal point
numeric variable user-specified precision, exact up to 131072 digits before the decimal point; up to 16383 digits after the decimal point
real 4 bytes variable-precision, inexact 6 decimal digits precision
double precision 8 bytes variable-precision, inexact 15 decimal digits precision
smallserial 2 bytes small autoincrementing integer 1 to 32767
serial 4 bytes autoincrementing integer 1 to 2147483647
bigserial 8 bytes large autoincrementing integer 1 to 9223372036854775807
 

Character Types

Name Description
character varying(n), varchar(n) variable-length with limit
character(n), char(n) fixed-length, blank padded
text variable unlimited length
*1 : signed data type = signed int, unsigned = unsigned int.
By default int data is signed ( meaning could be positive or negative). Unsigned data type is always non-negative type.