PostgreSQL like Oracle supports record data types but unlike Oracle, PostgreSQL doesn’t support collections of record data types. Here’s an example of how to define a PostgreSQL composite data type, and how to use it as a column’s data type.
CREATE TYPE address_type AS ( street_address VARCHAR , city VARCHAR , state VARCHAR , zip_code VARCHAR ); |
Then, you define an ADDRESS table, like:
CREATE TABLE address ( address_id SERIAL , address_struct ADDRESS_TYPE ); |
You can now insert rows like:
-- Insert the first row. INSERT INTO address ( address_struct ) VALUES (('52 Hubble Street','Lexington','KY','40511-1225')); -- Insert the second row. INSERT INTO address ( address_struct ) VALUES (('54 Hubble Street','Lexington','KY','40511-1225')); |
Then, you can query them like this:
SELECT * FROM address; |
It returns:
address_id | address_struct
------------+----------------------------------------------
1 | ("52 Hubble Street",Lexington,KY,40511-1225)
2 | ("54 Hubble Street",Lexington,KY,40511-1225)
(2 rows) |
You must use parentheses around the ADDRESS_STRUCT column to query individual items, like:
SELECT address_id , (address_struct).street_address , (address_struct).city , (address_struct).state , (address_struct).zip_code FROM address; |
It returns output like a table:
address_id | street_address | city | state | zip_code
------------+------------------+-----------+-------+------------
1 | 52 Hubble Street | Lexington | KY | 40511-1225
2 | 54 Hubble Street | Lexington | KY | 40511-1225
(2 rows) |
While you can define a table that holds an array of a composite type, there’s no syntax that appears to work with an array of a composite type. I hope this helps those interested in implementing record structures in PostgreSQL.