Database Reference
In-Depth Information
CHAPTER 5
Data Types
PostgreSQL supports the workhorse data types of any database: numerics, strings, dates
and times, and Booleans. But PostgreSQL sprints ahead by adding support for arrays,
datetimes with time zones, time intervals, ranges, JSON, XML, and many more types.
If that's not enough, you can invent custom types. In this chapter, we don't intend to
cover every data type. For that, there's always the manual. We'll focus on showing you
some of the data types that are unique to PostgreSQL and nuances of common data
types.
No data type would be useful without the functions and operators used to navigate and
work with it. PostgreSQL has an army of functions and operators that cater to each data
type, and many extensions add their own. We'll cover some of the more popular ones
in this chapter.
When we use the term
function
, we're talking about something that's
of the form
f(
x
)
. When we use the term
operator
, we're talking about
something that's symbolic and or unary (having only one argument)
or binary (having two arguments) such as
+, -, *, /
. The sim‐
plest operator is a symbol alias for a function that takes one or more
arguments. When using operators, keep in mind that the same sym‐
bol can take on a different meaning when applied to different data
types. For example, the plus sign means adding for numerics but
unioning for ranges.
Numerics
You will find your everyday integers, decimals, and floating point numbers in Post‐
greSQL. Of the numeric types, we want to discuss serial data types and a nifty function
to quickly generate arithmetic series of integers.
