Using list type

Use a list when the order of elements matter or when you need to store same value multiple times.

A list has a form much like a set, in that a list groups and stores values. Unlike a set, the values stored in a list do not need to be unique and can be duplicated. In addition, a list stores the elements in a particular order and may be inserted or retrieved according to an index value.

Use the list data type to store data that has a possible many-to-many relationship with another column. For example, in the example below, a list called events stores all the race events on an upcoming calendar.

Each month and year pairing might have several events occurring, and the races are stored in a list. The list can be ordered so that the races appear in the order that they will take place, rather than alphabetical order.


Define events in a table upcoming_calendar. Each event listed in the list will have a text data type. The following example shows the table and the initial rows.
CREATE TABLE IF NOT EXISTS cycling.upcoming_calendar (
  year int,
  month int,
  events list<text>,
  PRIMARY KEY (year, month)
 year | month | events
 2015 |     6 | ['Criterium du Dauphine', 'Tour de Suisse']
 2015 |     7 |                          ['Tour de France']

(2 rows)