Using map type
Use a map when pairs of related elements must be stored as a key-value pair.
A map relates one item to another with a key-value pair. For each key, only one value may exist, and duplicates cannot be stored. Both the key and the value are designated with a data type.
Using the map type, you can store timestamp-related information in user profiles. Each element of the map is internally stored as a single column that you can modify, replace, delete, and query. Each element can have an individual time-to-live and expire when the TTL ends.
Procedure
Define
teams
in a table cyclist_teams
. Each
team listed in the map
will have an integer
data type for the year
a cyclist belonged to the team and a
text
data type for the team name
. The map
collection is specified with a map column name and the pair of data types
enclosed in angle brackets. The following example shows the table and the
initial row.
CREATE TABLE IF NOT EXISTS cycling.cyclist_teams ( id uuid PRIMARY KEY, firstname text, lastname text, teams map<int, text> );
id | firstname | lastname | teams
--------------------------------------+-----------+----------+---------------------------------------------------------------------------
---------
5b6962dd-3f90-4c93-8f61-eabfa4a803e2 | Marianne | VOS | {2014: 'Rabobank-Liv Woman Cycling Team', 2015: 'Rabobank-Liv Woman Cyclin
g Team'}
(1 rows)